Уткин Юрий Николаевич

Научные интересы

Научные интересы Ю.Н.Уткина лежат в области исследования ядов животных, включая поиск в ядах, выделение и изучение биологической активности белков с новыми фармакологическими свойствами. Основное направление исследований – полипептидные соединения, взаимодействующие с Cys-петельными рецепторами.

Премии и заслуги

 

Ю.Н.Уткин награжден Почетной грамотой Российской  академии наук «За многолетнюю и плодотворную работу в Российской  академии наук и в связи с 275-летием Академии» и медалью «К 850-летию Москвы», являлся лауреатом конкурса на присуждение Государственных научных стипендий для ученых (1997-2002 гг.).

Членство в научных обществах

Член

международного общества токсинологии, европейского нейрохимического общества, американского общества биохимии и молекулярной биологии.

Избранные публикации

  1. Dubovskii P.V., Dubinnyi M.A., Volynsky P.E., Pustovalova Y.E., Konshina A.G., Utkin Y.N., Arseniev A.S., Efremov R.G. (2017). Impact of membrane partitioning on the spatial structure of an S-type cobra cytotoxin. J. Biomol. Struct. Dyn. , 1–16 [+]

    Cobra cytotoxins (CTs) belong to the three-fingered protein family. They are classified into S- and P-types, the latter exhibiting higher membrane-perturbing capacity. In this work, we investigated the interaction of CTs with phospholipid bilayers, using coarse-grained (CG) and full-atom (FA) molecular dynamics (MD). The object of this work is a CT of an S-type, cytotoxin I (CT1) from N.oxiana venom. Its spatial structure in aqueous solution and in the micelles of dodecylphosphocholine (DPC) were determined by (1)H-NMR spectroscopy. Then, via CG- and FA MD-computations, we evaluated partitioning of CT1 molecule into palmitoyloleoylphosphatidylcholine (POPC) membrane, using the toxin spatial models, obtained either in aqueous solution, or detergent micelle. The latter model exhibits minimal structural changes upon partitioning into the membrane, while the former deviates from the starting conformation, loosing the tightly bound water molecule in the loop-2. These data show that the structural changes elicited by CT1 molecule upon incorporation into DPC micelle take place likely in the lipid membrane, although the mode of the interaction of this toxin with DPC micelle (with the tips of the all three loops) is different from its mode in POPC membrane (primarily with the tip of the loop-1 and both the tips of the loop-1 and loop-2).

    ID:1943
  2. Tran T.V., Hoang A.N., Nguyen T.T.T., Phung T.V., Nguyen K.C., Osipov A.V., Ivanov I.A., Tsetlin V.I., Utkin Y.N. (2017). Anticoagulant Activity of Low-Molecular Weight Compounds from Heterometrus laoticus Scorpion Venom. Toxins (Basel) 9 (11), [+]

    Scorpion venoms are complex polypeptide mixtures, the ion channel blockers and antimicrobial peptides being the best studied components. The coagulopathic properties of scorpion venoms are poorly studied and the data about substances exhibiting these properties are very limited. During research on the Heterometrus laoticus scorpion venom, we have isolated low-molecular compounds with anticoagulant activity. Determination of their structure has shown that one of them is adenosine, and two others are dipeptides LeuTrp and IleTrp. The anticoagulant properties of adenosine, an inhibitor of platelet aggregation, are well known, but its presence in scorpion venom is shown for the first time. The dipeptides did not influence the coagulation time in standard plasma coagulation tests. However, similarly to adenosine, both peptides strongly prolonged the bleeding time from mouse tail and in vitro clot formation in whole blood. The dipeptides inhibited the secondary phase in platelet aggregation induced by ADP, and IleTrp decreased an initial rate of platelet aggregation induced by collagen. This suggests that their anticoagulant effects may be realized through the deterioration of platelet function. The ability of short peptides from venom to slow down blood coagulation and their presence in scorpion venom are established for the first time. Further studies are needed to elucidate the precise molecular mechanism of dipeptide anticoagulant activity.

    ID:1955
  3. Osipov A.V., Terpinskaya T.I., Kuznetsova T.E., Ryzhkovskaya E.L., Lukashevich V.S., Rudnichenko J.A., Ulashchyk V.S., Starkov V.G., Utkin Y.N. (2017). Cobra Venom Factor and Ketoprofen Abolish the Antitumor Effect of Nerve Growth Factor from Cobra Venom. Toxins (Basel) 9 (9), [+]

    We showed recently that nerve growth factor (NGF) from cobra venom inhibited the growth of Ehrlich ascites carcinoma (EAC) inoculated subcutaneously in mice. Here, we studied the influence of anti-complementary cobra venom factor (CVF) and the non-steroidal anti-inflammatory drug ketoprofen on the antitumor NGF effect, as well as on NGF-induced changes in EAC histological patterns, the activity of lactate and succinate dehydrogenases in tumor cells and the serum level of some cytokines. NGF, CVF and ketoprofen reduced the tumor volume by approximately 72%, 68% and 30%, respectively. The antitumor effect of NGF was accompanied by an increase in the lymphocytic infiltration of the tumor tissue, the level of interleukin 1β and tumor necrosis factor α in the serum, as well as the activity of lactate and succinate dehydrogenases in tumor cells. Simultaneous administration of NGF with either CVF or ketoprofen abolished the antitumor effect and reduced all other effects of NGF, whereas NGF itself significantly decreased the antitumor action of both CVF and ketoprofen. Thus, the antitumor effect of NGF critically depended on the status of the immune system and was abolished by the disturbance of the complement system; the disturbance of the inflammatory response canceled the antitumor effect as well.

    ID:1843
  4. Alekseeva A.S., Tretiakova D.S., Chernikov V.P., Utkin Y.N., Molotkovsky J.G., Vodovozova E.L., Boldyrev I.A. (2017). Heterodimeric V. nikolskii phospholipases A2 induce aggregation of the lipid bilayer. Toxicon 133, 169–179 [+]

    We report that the action of the heterodimeric phospholipases A2 (PLA2s) from Vipera nikolskii, which comprises enzymatically active basic subunit and inactive acidic PLA2 homologue, on the lipid bilayer results in the aggregation and stacking of bilayers. These processes are demonstrated using two independent methods (fluorescence spectroscopy and electron microscopy). Aggregation of bilayers is possible because both subunits of the V. nikolskii heterodimer contain a membrane-binding site (also known as IBS). Thus, when the two IBSs bind to the membrane, the heterodimer acts as a connecting agent. Heterodimers induce aggregation of negatively charged bilayers composed of phosphatidylglycerol and do not induce aggregation of neutral bilayers composed of phosphatidylcholine.

    ID:1797
  5. Utkin Y.N. (2017). Modern trends in animal venom research - omics and nanomaterials. World J Biol Chem 8 (1), 4–12 [+]

    Animal venom research is a specialized investigation field, in which a number of different methods are used and this array is constantly expanding. Thus, recently emerged omics and nanotechnologies have already been successfully applied to venom research. Animal venoms have been studied for quite a long time. The traditional reductionist approach has been to isolate individual toxins and then study their structure and function. Unfortunately, the characterization of the venom as a whole system and its multiple effects on an entire organism were not possible until recent times. The development of new methods in mass spectrometry and sequencing have allowed such characterizations of venom, encompassing the identification of new toxins present in venoms at extremely low concentrations to changes in metabolism of prey organisms after envenomation. In particular, this type of comprehensive research has become possible due to the development of the various omics technologies: Proteomics, peptidomics, transcriptomics, genomics and metabolomics. As in other research fields, these omics technologies ushered in a revolution for venom studies, which is now entering the era of big data. Nanotechnology is a very new branch of technology and developing at an extremely rapid pace. It has found application in many spheres and has not bypassed the venom studies. Nanomaterials are quite promising in medicine, and most studies combining venoms and nanomaterials are dedicated to medical applications. Conjugates of nanoparticles with venom components have been proposed for use as drugs or diagnostics. For example, nanoparticles conjugated with chlorotoxin - a toxin in scorpion venom, which has been shown to bind specifically to glioma cells - are considered as potential glioma-targeted drugs, and conjugates of neurotoxins with fluorescent semiconductor nanoparticles or quantum dots may be used to detect endogenous targets expressed in live cells. The data on application of omics and nanotechnologies in venom research are systematized concisely in this paper.

    ID:1842
  6. Vulfius C.A., Kasheverov I.E., Kryukova E.V., Spirova E.N., Shelukhina I.V., Starkov V.G., Andreeva T.V., Faure G., Zouridakis M., Tsetlin V.I., Utkin Y.N. (2017). Pancreatic and snake venom presynaptically active phospholipases A2 inhibit nicotinic acetylcholine receptors. PLoS ONE 12 (10), e0186206 [+]

    Phospholipases A2 (PLA2s) are enzymes found throughout the animal kingdom. They hydrolyze phospholipids in the sn-2 position producing lysophospholipids and unsaturated fatty acids, agents that can damage membranes. PLA2s from snake venoms have numerous toxic effects, not all of which can be explained by phospholipid hydrolysis, and each enzyme has a specific effect. We have earlier demonstrated the capability of several snake venom PLA2s with different enzymatic, cytotoxic, anticoagulant and antiproliferative properties, to decrease acetylcholine-induced currents in Lymnaea stagnalis neurons, and to compete with α-bungarotoxin for binding to nicotinic acetylcholine receptors (nAChRs) and acetylcholine binding protein. Since nAChRs are implicated in postsynaptic and presynaptic activities, in this work we probe those PLA2s known to have strong presynaptic effects, namely β-bungarotoxin from Bungarus multicinctus and crotoxin from Crotalus durissus terrificus. We also wished to explore whether mammalian PLA2s interact with nAChRs, and have examined non-toxic PLA2 from porcine pancreas. It was found that porcine pancreatic PLA2 and presynaptic β-bungarotoxin blocked currents mediated by nAChRs in Lymnaea neurons with IC50s of 2.5 and 4.8 μM, respectively. Crotoxin competed with radioactive α-bungarotoxin for binding to Torpedo and human α7 nAChRs and to the acetylcholine binding protein. Pancreatic PLA2 interacted similarly with these targets; moreover, it inhibited radioactive α-bungarotoxin binding to the water-soluble extracellular domain of human α9 nAChR, and blocked acetylcholine induced currents in human α9α10 nAChRs heterologously expressed in Xenopus oocytes. These and our earlier results show that all snake PLA2s, including presynaptically active crotoxin and β-bungarotoxin, as well as mammalian pancreatic PLA2, interact with nAChRs. The data obtained suggest that this interaction may be a general property of all PLA2s, which should be proved by further experiments.

    ID:1873
  7. Shulepko M.A., Lyukmanova E.N., Shenkarev Z.O., Dubovskii P.V., Astapova M.V., Feofanov A.V., Arseniev A.S., Utkin Y.N., Kirpichnikov M.P., Dolgikh D.A. (2016). Towards universal approach for bacterial production of three-finger Ly6/uPAR proteins: Case study of cytotoxin I from cobra N. oxiana. Protein Expr. Purif. 130, 13–20 [+]

    Cytotoxins or cardiotoxins is a group of polycationic toxins from cobra venom belonging to the 'three-finger' protein superfamily (Ly6/uPAR family) which includes small β-structural proteins (60-90 residues) with high disulfide bond content (4-5 disulfides). Due to a high cytotoxic activity for cancer cells, cytotoxins are considered as potential anticancer agents. Development of the high-throughput production methods is required for the prospective applications of cytotoxins. Here, efficient approach for bacterial production of recombinant analogue of cytotoxin I from N. oxiana containing additional N-terminal Met-residue (rCTX1) was developed. rCTX1 was produced in the form of E. coli inclusion bodies. Refolding in optimized conditions provided ∼6 mg of correctly folded protein from 1 L of bacterial culture. Cytotoxicity of rCTX1 for C6 rat glioma cells was found to be similar to the activity of wild type CTX1. The milligram quantities of (13)C,(15)N-labeled rCTX1 were obtained. NMR study confirmed the similarity of the spatial structures of recombinant and wild-type toxins. Additional Met residue does not perturb the overall structure of the three-finger core. The analysis of available data for different Ly6/uPAR proteins of snake and human origin revealed that efficiency of their folding in vitro is correlated with the number of proline residues in the third loop and the surface area of hydrophobic residues buried within the protein interior. The obtained data indicate that hydrophobic core is important for the folding of proteins with high disulfide bond content. Developed expression method opens new possibilities for structure-function studies of CTX1 and other related three-finger proteins.

    ID:1599
  8. Lyukmanova E.N., Shulepko M.A., Shenkarev Z.O., Kasheverov I.E., Chugunov A.O., Kulbatskii D.S., Myshkin M.Y., Utkin Y.N., Efremov R.G., Tsetlin V.I., Arseniev A.S., Kirpichnikov M.P., Dolgikh D.A. (2016). Central loop of non-conventional toxin WTX from Naja kaouthia is important for interaction with nicotinic acetylcholine receptors. Toxicon 119, 274–9 [+]

    'Three-finger' toxin WTX from Naja kaouthia interacts with nicotinic and muscarinic acetylcholine receptors (nAChRs and mAChRs). Mutagenesis and competition experiments with (125)I-α-bungarotoxin revealed that Arg31 and Arg32 residues from the WTX loop II are important for binding to Torpedo californica and human α7 nAChRs. Computer modeling suggested that loop II occupies the orthosteric binding site at α7 nAChR. The similar toxin interface was previously described as a major determinant of allosteric interactions with mAChRs.

    ID:1598
  9. Terpinskaya T.I., Ulashchik V.S., Osipov A.V., Tsetlin V.I., Utkin Y.N. (2016). Suppression of Ehrlich carcinoma growth by cobra venom factor. Dokl. Biol. Sci. 470 (1), 240–243 [+]

    Cobra venom factor (CVF) depletes the complement system of the blood by forming stable convertase C3/C5 of the alternative pathway. We found that CVF from the Thailand cobra venom slows down the growth of subcutaneous Ehrlich carcinoma (EC) in mice at a dose of 1.7 nmol/g. Previously, we described a similar effect for the nerve growth factor (NGF) from the venom of this cobra. However, these factors did not exhibit either synergy or additive effect. On the contrary, they neutralized the antitumor effect of each other when they were administered simultaneously. Therefore, on the one hand, the NGF antitumor effect against EC manifests itself under the conditions of inflammation, and normal functioning of the complement system is necessary for this effect to occur. On the other hand, suppression of the humoral immune system leads to a slowdown of the EC growth, but administration of NGF prevents this.

    ID:1954
  10. Kovalchuk S.I., Ziganshin R.H., Starkov V.G., Tsetlin V.I., Utkin Y.N. (2016). Quantitative Proteomic Analysis of Venoms from Russian Vipers of Pelias Group: Phospholipases A₂ are the Main Venom Components. Toxins (Basel) 8 (4), 105 [+]

    С использованием количественного протеомного анализа изучены яды четырех видов гадюк (V. kaznakovi, V. nikolskii, V. orlovi и V. renardi), которые обитают в различных регионах России. Установлено, что в отличие от ядов ранее изученных видов гадюк, в которых доминирующим являются металлоротеиназы, основными компонентами исследованных в данной работе ядов являются фософлипазы А2, содержание которых колеблется от 24 до 65%.

    ID:1603
  11. Ziganshin R.H., Kovalchuk S.I., Arapidi G.P., Starkov V.G., Hoang A.N., ThiNguyen T.T., Nguyen K.C., Shoibonov B.B., Tsetlin V.I., Utkin Y.N. (2015). Quantitative proteomic analysis of Vietnamese krait venoms: Neurotoxins are the major components in Bungarus multicinctus and phospholipases A2 in Bungarus fasciatus. Toxicon 107 (Pt B), 197–209 [+]

    Kraits are venomous snakes of genus Bungarus from family Elapidae. Krait venoms are generally neurotoxic, but toxicity strongly depends on the particular species and regional origin of snakes. We analyzed the proteomes of Vietnamese Bungarus multicinctus and Bungarus fasciatus venoms both qualitatively and quantitatively. It should be noted that no proteomic data for B. multicinctus venom existed so far. We have found that in this venom, almost half (45%) of the proteins by weight was represented by β-bungarotoxins, followed by three finger toxins (28%) and phospholipases A2 (16%), other proteins being present at the level of 1-3%. In B. fasciatus venom, phospholipase A2 was the main component (71%), followed by oxidase of l-amino acids (8%), acetylcholinesterase (5%) and metalloproteinases (4%). Unexpectedly, extremely low amount of three finger toxins (1%) was found in this venom. Interestingly, the presence of complement depleting factor was observed in both venoms. Although our data showed the presence of the same toxin families in Vietnamese krait venoms as those found earlier in the venoms of kraits from other geographic regions, their relative ratio is completely different. This concerns especially B. fasciatus venom with predominant content of phospholipases A2 and very low amount of three finger toxins.

    ID:1466
  12. Lyukmanova E.N., Shenkarev Z.O., Shulepko M.A., Paramonov A.S., Chugunov A.O., Janickova H., Dolejsi E., Dolezal V., Utkin Y.N., Tsetlin V.I., Arseniev A.S., Efremov R.G., Dolgikh D.A., Kirpichnikov M.P. (2015). Structural Insight into Specificity of Interactions between Nonconventional Three-finger Weak Toxin from Naja kaouthia (WTX) and Muscarinic Acetylcholine Receptors. J. Biol. Chem. 290 (39), 23616–30 [+]

    Weak toxin from Naja kaouthia (WTX) belongs to the group of nonconventional "three-finger" snake neurotoxins. It irreversibly inhibits nicotinic acetylcholine receptors and allosterically interacts with muscarinic acetylcholine receptors (mAChRs). Using site-directed mutagenesis, NMR spectroscopy, and computer modeling, we investigated the recombinant mutant WTX analogue (rWTX) which, compared with the native toxin, has an additional N-terminal methionine residue. In comparison with the wild-type toxin, rWTX demonstrated an altered pharmacological profile, decreased binding of orthosteric antagonist N-methylscopolamine to human M1- and M2-mAChRs, and increased antagonist binding to M3-mAChR. Positively charged arginine residues located in the flexible loop II were found to be crucial for rWTX interactions with all types of mAChR. Computer modeling suggested that the rWTX loop II protrudes to the M1-mAChR allosteric ligand-binding site blocking the entrance to the orthosteric site. In contrast, toxin interacts with M3-mAChR by loop II without penetration into the allosteric site. Data obtained provide new structural insight into the target-specific allosteric regulation of mAChRs by "three-finger" snake neurotoxins.

    ID:1394
  13. Kudryavtsev D.S., Shelukhina I.V., Son L.V., Ojomoko L.O., Kryukova E.V., Lyukmanova E.N., Zhmak M.N., Dolgikh D.A., Ivanov I.A., Kasheverov I.E., Starkov V.G., Ramerstorfer J., Sieghart W., Tsetlin V.I., Utkin Y.N. (2015). Neurotoxins from Snake Venoms and α-Conotoxin ImI Inhibit Functionally Active Ionotropic GABA Receptors. J. Biol. Chem. , [+]

    Ionotropic receptors of γ-aminobutyric acid (GABAAR) regulate neuronal inhibition and are targeted by benzodiazepines and general anesthetics. We show that a fluorescent derivative of α-cobratoxin (α-Ctx), belonging to the family of three-finger toxins (TFTs) from snake venoms, specifically stained the α1β3γ2 receptor; at 10 μM α-Ctx completely blocked GABA-induced currents in this receptor expressed in Xenopus oocytes (IC50 = 236 nM) and less potently inhibited α1β2γ2 ≈ α2β2γ2 > α5β2γ2 > α2β3γ2 and α1β3δ GABAARs. The α1β3γ2 receptor was also inhibited by some other TFTs: long α-neurotoxin Ls III and non-conventional toxin WTX. α-Conotoxin ImI displayed inhibitory activity as well. Electrophysiology experiments showed mixed competitive and non-competitive α-Ctx action. Fluorescent α-Ctx, however, could be displaced by muscimol indicating that most of the α-Ctx binding sites overlap with the orthosteric sites at the β/α subunit interface. Modeling and molecular dynamic studies indicated that α-Ctx or α-bungarotoxin seem to interact with GABAAR in a way similar to their interaction with the acetylcholine-binding protein or the ligand-binding domain of nicotinic receptors. This was supported by mutagenesis studies and experiments with α-conotoxin ImI and a chimeric Naja oxiana α-neurotoxin indicating that the major role in α-Ctx binding to GABAAR is played by the tip of its central loop II accomodating under loop C of the receptors.

    ID:1307
  14. Utkin Y.N. (2015). Animal venom studies: Current benefits and future developments. World J Biol Chem 6 (2), 28–33 [+]

    Poisonous organisms are represented in many taxa, including kingdom Animalia. During evolution, animals have developed special organs for production and injection of venoms. Animal venoms are complex mixtures, compositions of which depend on species producing venom. The most known and studied poisonous terrestrial animals are snakes, scorpions and spiders. Among marine animals, these are jellyfishes, anemones and cone snails. The toxic substances in the venom of these animals are mainly of protein and peptide origin. Recent studies have indicated that the single venom may contain up to several hundred different components producing diverse physiological effects. Bites or stings by certain poisonous species result in severe envenomations leading in some cases to death. This raises the problem of bite treatment. The most effective treatment so far is the application of antivenoms. To enhance the effectiveness of such treatments, the knowledge of venom composition is needed. On the other hand, venoms contain substances with unique biological properties, which can be used both in basic science and in clinical applications. The best example of toxin application in basic science is α-bungarotoxin the discovery of which made a big impact on the studies of nicotinic acetylcholine receptor. Today compositions of venom from many species have already been examined. Based on these data, one can conclude that venoms contain a large number of individual components belonging to a limited number of structural types. Often minor changes in the amino acid sequence give rise to new biological properties. Change in the living conditions of poisonous animals lead to alterations in the composition of venoms resulting in appearance of new toxins. At the same time introduction of new methods of proteomics and genomics lead to discoveries of new compounds, which may serve as research tools or as templates for the development of novel drugs. The application of these sensitive and comprehensive methods allows studying either of venoms available in tiny amounts or of low abundant components in already known venoms.

    ID:1468
  15. Kudryavtsev D., Shelukhina I., Vulfius C., Makarieva T., Stonik V., Zhmak M., Ivanov I., Kasheverov I., Utkin Y., Tsetlin V. (2015). Natural compounds interacting with nicotinic acetylcholine receptors: from low-molecular weight ones to peptides and proteins. Toxins (Basel) 7 (5), 1683–701 [+]

    Nicotinic acetylcholine receptors (nAChRs) fulfill a variety of functions making identification and analysis of nAChR subtypes a challenging task. Traditional instruments for nAChR research are d-tubocurarine, snake venom protein α-bungarotoxin (α-Bgt), and α-conotoxins, neurotoxic peptides from Conus snails. Various new compounds of different structural classes also interacting with nAChRs have been recently identified. Among the low-molecular weight compounds are alkaloids pibocin, varacin and makaluvamines C and G. 6-Bromohypaphorine from the mollusk Hermissenda crassicornis does not bind to Torpedo nAChR but behaves as an agonist on human α7 nAChR. To get more selective α-conotoxins, computer modeling of their complexes with acetylcholine-binding proteins and distinct nAChRs was used. Several novel three-finger neurotoxins targeting nAChRs were described and α-Bgt inhibition of GABA-A receptors was discovered. Information on the mechanisms of nAChR interactions with the three-finger proteins of the Ly6 family was found. Snake venom phospholipases A2 were recently found to inhibit different nAChR subtypes. Blocking of nAChRs in Lymnaea stagnalis neurons was shown for venom C-type lectin-like proteins, appearing to be the largest molecules capable to interact with the receptor. A huge nAChR molecule sensible to conformational rearrangements accommodates diverse binding sites recognizable by structurally very different compounds.

    ID:1306
  16. Ghazaryan N.A., Ghulikyan L., Kishmiryan A., Andreeva T.V., Utkin Y.N., Tsetlin V.I., Lomonte B., Ayvazyan N.M. (2015). Phospholipases a2 from Viperidae snakes: Differences in membranotropic activity between enzymatically active toxin and its inactive isoforms. Biochim. Biophys. Acta 1848 (2), 463–8 [+]

    We describe the interaction of various phospholipases A2 (PLA2) from snake venoms of the family Viperidae (Macrovipera lebetina obtusa, Vipera ursinii renardi, Bothrops asper) with giant unilamellar vesicles (GUVs) composed of natural brain phospholipids mixture, visualized through fluorescence microscopy. The membrane fluorescent probes 8-anilino-1-naphthalenesulfonicacid (ANS), LAUDRAN and PRODAN were used to assess the state of the membrane and specifically mark the lipid packing and membrane fluidity. Our results have shown that the three PLA2s which contain either of aspartic acid, serine, or lysine residues at position 49 in the catalytic center, have different effects on the vesicles. The PLA2 with aspartic acid at this position causes the oval deformation of the vesicles, while serine and lysine-containing enzymes lead to an appreciable increase of fluorescence intensity in the vesicles membrane, wherein the shape and dimensions of GUVs have not changed, but in this case GUV aggregation occurs. LAURDAN and PRODAN detect the extent of water penetration into the bilayer surface. We calculated generalized polarization function (GP), showing that for all cases (D49 PLA2, S49 PLA2 and K49 PLA2) both LAUDRAN and PRODAN GP values decrease. A higher LAURDAN GP is indicative of low water penetration in the lipid bilayer in case of K49 PLA2 compared with D49 PLA2, whereas the PRODAN mainly gives information when lipid is in liquid crystalline phase.

    ID:1161
  17. Utkin Y.N., Kasheverov I.E., Kudryavtsev D.S., Andreeva T.V., Starkov V.G., Ziganshin R.H., Kuznetsov D.V., Anh H.N., Thao N.T., Khoa N.C., Tsetlin V.I. (2015). Nonconventional three-finger toxin BMLCL from krait Bungarus multicinctus venom with high affinity interacts with nicotinic acetylcholine receptors. Dokl. Biochem. Biophys. 464, 294–7 [+]

    Nonconventional three-finger toxin BMLCL was isolated from B. multicinctus venom, and its interaction with different subtypes of nicotinic acetylcholine receptor (nAChR) was studied. It was found that BMLCL is able to interact with high efficiency with both α7 and muscle type nAChRs.

    ID:1477
  18. Дубовский П.В., Уткин Ю.Н. (2014). Цитотоксины кобр: структурная организация и антибактериальная активность. Acta Naturae 6 (3), 12–19 ID:1125
  19. Dubovskii P.V., Utkin Y.N. (2014). Cobra cytotoxins: structural organization and antibacterial activity. Acta Naturae 6 (3), 11–8 [+]

    Cardiotoxins (cytotoxins, CT) are β-structured proteins isolated from the venom of cobra. They consist of 59-61 amino acid residues, whose antiparallel chains form three 'fingers'. In contrast to neurotoxins with an overall similar fold, CTs are amphiphilic. The amphiphilicity is caused by positively charged lysine and arginine residues flanking the tips of the loops that consist primarily of hydrophobic amino acids. A similar distribution of amino acid residues is typical for linear (without disulfide bonds) cationic cytolytic peptides from the venoms of other snakes and insects. Many of them are now considered to be lead compounds in combatting bacterial infections and cancer. In the present review, we summarize the data on the antibacterial activity of CTs and compare it to the activity of linear peptides.

    ID:1111
  20. Osipov A.V., Terpinskaya T.I., Kryukova E.V., Ulaschik V.S., Paulovets L.V., Petrova E.A., Blagun E.V., Starkov V.G., Utkin Y.N. (2014). Nerve growth factor from cobra venom inhibits the growth of Ehrlich tumor in mice. Toxins (Basel) 6 (3), 784–95 [+]

    The effects of nerve growth factor (NGF) from cobra venom (cvNGF) on growth of Ehrlich ascites carcinoma (EAC) cells inoculated subcutaneously in mice have been studied. The carcinoma growth slows down, but does not stop, during a course of cvNGF injections and restores after the course has been discontinued. The maximal anti-tumor effect has been observed at a dose of 8 nmoles cvNGF/kg body weight. cvNGF does not impact on lifespan of mice with grafted EAC cells. K252a, a tyrosine kinase inhibitor, attenuates the anti-tumor effect of cvNGF indicating the involvement of TrkA receptors in the process. cvNGF has induced also increase in body weight of the experimental animals. In overall, cvNGF shows the anti-tumor and weight-increasing effects which are opposite to those described for mammalian NGF (mNGF). However in experiments on breast cancer cell line MCF-7 cvNGF showed the same proliferative effects as mNGF and had no cytotoxic action on tumor cells in vitro. These data suggest that cvNGF slows down EAC growth via an indirect mechanism in which TrkA receptors are involved.

    ID:1467
  21. Hoang A.N., Vo H.D., Vo N.P., Kudryashova K.S., Nekrasova O.V., Feofanov A.V., Kirpichnikov M.P., Andreeva T.V., Serebryakova M.V., Tsetlin V.I., Utkin Y.N. (2014). Vietnamese Heterometrus laoticus scorpion venom: evidence for analgesic and anti-inflammatory activity and isolation of new polypeptide toxin acting on Kv1.3 potassium channel. Toxicon 77, 40–8 [+]

    The scorpion Heterometrus laoticus (Scorpionidae) inhabits Indochinese peninsula and is widely distributed in South-West Vietnam. Since no human fatalities caused by H. laoticus stings were reported, no systematic characterization of the venom was earlier done. In this study we report on biological activity of the venom from H. laoticus caught in Vietnamese province An Giang. The venom manifested a very low acute toxicity with LD50 of about 190 mg/kg body weight in mice at subcutaneous (s.c.) injection and 12 mg/kg at intravenous injection. The venom analgesic effects using tail immersion and writhing tests as well as anti-inflammatory effect using carrageenan test were analyzed at doses of 9.5 and 19 mg/kg at s.c. injections. It was found that at two doses tested H. laoticus venom showed both anti-nociceptive and anti-inflammatory activity. The venom was fractionated by means of gel-filtration and reversed-phase HPLC. As a result several polypeptide toxins were isolated and new toxin hetlaxin was identified. Its amino acid sequence was determined and binding to the extracellular vestibule of the K⁺-conducting pore of Kv1.1 and Kv1.3 potassium channels was studied. Hetlaxin belongs to the scorpion alpha-toxin family and is the first toxin isolated from H. laoticus venom which possesses high affinity (K(i) 59 nM) to Kv1.3 potassium channel.

    ID:1082
  22. Vulfius C.A., Kasheverov I.E., Starkov V.G., Osipov A.V., Andreeva T.V., Filkin S.Y., Gorbacheva E.V., Astashev M.E., Tsetlin V.I., Utkin Y.N. (2014). Inhibition of nicotinic acetylcholine receptors, a novel facet in the pleiotropic activities of snake venom phospholipases A2. PLoS ONE 9 (12), e115428 [+]

    Phospholipases A2 represent the most abundant family of snake venom proteins. They manifest an array of biological activities, which is constantly expanding. We have recently shown that a protein bitanarin, isolated from the venom of the puff adder Bitis arietans and possessing high phospholipolytic activity, interacts with different types of nicotinic acetylcholine receptors and with the acetylcholine-binding protein. To check if this property is characteristic to all venom phospholipases A2, we have studied the capability of these enzymes from other snakes to block the responses of Lymnaea stagnalis neurons to acetylcholine or cytisine and to inhibit α-bungarotoxin binding to nicotinic acetylcholine receptors and acetylcholine-binding proteins. Here we present the evidence that phospholipases A2 from venoms of vipers Vipera ursinii and V. nikolskii, cobra Naja kaouthia, and krait Bungarus fasciatus from different snake families suppress the acetylcholine- or cytisine-elicited currents in L. stagnalis neurons and compete with α-bungarotoxin for binding to muscle- and neuronal α7-types of nicotinic acetylcholine receptor, as well as to acetylcholine-binding proteins. As the phospholipase A2 content in venoms is quite high, under some conditions the activity found may contribute to the deleterious venom effects. The results obtained suggest that the ability to interact with nicotinic acetylcholine receptors may be a general property of snake venom phospholipases A2, which add a new target to the numerous activities of these enzymes.

    ID:1162
  23. Utkin Y.N. (2013). Three-finger toxins, a deadly weapon of elapid venom--milestones of discovery. Toxicon 62, 50–5 [+]

    Three-finger toxins (TFTs) are the main venom components of snakes from Elapidae family. Amino acid sequences of more than five hundreds TFTs are determined; these toxins form one of the largest protein families present in snake venoms. The first TFT α-bungarotoxin was isolated almost half a century ago and so far it remains a valuable tool in the study of nicotinic acetylcholine receptors. TFTs possess diverse biological activities; for example, α-neurotoxins bind specifically with high affinity to nicotinic acetylcholine receptors, while cytotoxins induce non-specific lysis in great variety of cells. These toxins are widely used as instruments in different branches of life sciences. In this review the main landmarks in TFT study are considered. These are the discovery and isolation of TFTs, determination of their structure and mode of action as well as evolution and relationship within the family.

    ID:1469
  24. Dyachenko I.A., Murashev A.N., Andreeva T.V., Tsetlin V.I., Utkin Y.N. (2013). Analysis of nociceptive effects of neurotoxic phospholipase A2 from Vipera nikolskii venom in mice. J Venom Res 4, 1–4 [+]

    Phospholipases A2 are represented in snake venoms by several types and possess diverse biological activities including neurotoxicity. Previously, we isolated and characterized two neurotoxic phospholipases A2 (HDP-1 and HDP-2) from the venom of Nikolski's viper (Vipera nikolskii), which were heterodimers composed of two non-covalently bound subunits. Each heterodimer consisted of an enzymatically active basic subunit and an inactive acidic subunit. In this work, we studied the in vivo biological activity of HDP-2 in mice. The acute toxicity (LD50 = 0.38 μg/gm) and maximal tolerated dose (0.1 μg/gm) were determined. In the hot plate test, HDP-2 at the maximal tolerated dose, reliably prolonged the time of the mouse staying on the plate. However, taking into account the neurotoxicity of HDP-2, we believe that this effect may be explained by a general intoxication rather than specific decrease of pain sensitivity. In this respect HDP-2 differs from other heterodimeric phospholipases A2 like crotoxin, which possess analgesic activity. This difference can be explained by the dissimilarity in the structure of the acidic subunits, suggesting an important role of this subunit in analgesic activity.

    ID:1470
  25. Utkin Y.N., Weise C., Kasheverov I.E., Andreeva T.V., Kryukova E.V., Zhmak M.N., Starkov V.G., Hoang N.A., Bertrand D., Ramerstorfer J., Sieghart W., Thompson A.J., Lummis S.C., Tsetlin V.I. (2012). Azemiopsin from Azemiops feae viper venom, a novel polypeptide ligand of nicotinic acetylcholine receptor. J. Biol. Chem. 287 (32), 27079–86 [+]

    Azemiopsin, a novel polypeptide, was isolated from the Azemiops feae viper venom by combination of gel filtration and reverse-phase HPLC. Its amino acid sequence (DNWWPKPPHQGPRPPRPRPKP) was determined by means of Edman degradation and mass spectrometry. It consists of 21 residues and, unlike similar venom isolates, does not contain cysteine residues. According to circular dichroism measurements, this peptide adopts a β-structure. Peptide synthesis was used to verify the determined sequence and to prepare peptide in sufficient amounts to study its biological activity. Azemiopsin efficiently competed with α-bungarotoxin for binding to Torpedo nicotinic acetylcholine receptor (nAChR) (IC(50) 0.18 ± 0.03 μm) and with lower efficiency to human α7 nAChR (IC(50) 22 ± 2 μm). It dose-dependently blocked acetylcholine-induced currents in Xenopus oocytes heterologously expressing human muscle-type nAChR and was more potent against the adult form (α1β1εδ) than the fetal form (α1β1γδ), EC(50) being 0.44 ± 0.1 μm and 1.56 ± 0.37 μm, respectively. The peptide had no effect on GABA(A) (α1β3γ2 or α2β3γ2) receptors at a concentration up to 100 μm or on 5-HT(3) receptors at a concentration up to 10 μm. Ala scanning showed that amino acid residues at positions 3-6, 8-11, and 13-14 are essential for binding to Torpedo nAChR. In biological activity azemiopsin resembles waglerin, a disulfide-containing peptide from the Tropidechis wagleri venom, shares with it a homologous C-terminal hexapeptide, but is the first natural toxin that blocks nAChRs and does not possess disulfide bridges.

    ID:1083
  26. Osipov A.V., Rucktooa P., Kasheverov I.E., Filkin S.Y., Starkov V.G., Andreeva T.V., Sixma T.K., Bertrand D., Utkin Y.N., Tsetlin V.I. (2012). Dimeric α-Cobratoxin X-ray Structure: LOCALIZATION OF INTERMOLECULAR DISULFIDES AND POSSIBLE MODE OF BINDING TO NICOTINIC ACETYLCHOLINE RECEPTORS. J. Biol. Chem. 287 (9), 6725–34 [+]

    Установлена кристаллическая структура и положение дисульфидных связей в димере α-кобратоксина (αСТ-αСТ). Внутримолекулярные дисульфиды в центральных петлях II были восстановлены и исследовано взаимодействие полученных производных с различными типами никотиновых холинорецепторов. Обнаружено, что дисульфиды петили II необходимы для взаимодействия с α7 типом рецептора, но не с α3β2.

    ID:651
  27. Vulfius C.A., Gorbacheva E.V., Starkov V.G., Osipov A.V., Kasheverov I.E., Andreeva T.V., Astashev M.E., Tsetlin V.I., Utkin Y.N. (2011). An unusual phospholipase A₂ from puff adder Bitis arietans venom--a novel blocker of nicotinic acetylcholine receptors. Toxicon 57 (5), 787–93 [+]

    The venoms of snakes from Viperidae family mainly influence the function of various blood components. However, the published data indicate that these venoms contain also neuroactive components, the most studied being neurotoxic phospholipases A₂ (PLA₂s). Earlier we have shown (Gorbacheva et al., 2008) that several Viperidae venoms blocked nicotinic acetylcholine receptors (nAChRs) and voltage-gated Ca²+ channels in isolated identified neurons of the fresh-water snail Lymnaea stagnalis. In this paper, we report on isolation from puff adder Bitis arietans venom and characterization of a novel protein bitanarin that reversibly blocks nAChRs. To isolate the protein, the venom of B. arietans was fractionated by gel-filtration, ion-exchange and reversed phase chromatography and fractions obtained were screened for capability to block nAChRs. The isolated protein competed with [¹²⁵I]iodinated α-bungarotoxin for binding to human α7 and Torpedo californica nAChRs, as well as to acetylcholine-binding protein from L. stagnalis, the IC₅₀ being 20 ± 1.5, 4.3 ± 0.2, and 10.6 ± 0.6 μM, respectively. It also blocked reversibly acetylcholine-elicited current in isolated L. stagnalis neurons with IC₅₀ of 11.4 μM. Mass-spectrometry analysis determined the molecular mass of 27.4 kDa and the presence of 28 cysteine residues forming 14 disulphide bonds. Edman degradation of the protein and tryptic fragments showed its similarity to PLA₂s from snake venoms. Indeed, the protein possessed high PLA₂ activity, which was 1.95 mmol/min/μmol. Bitanarin is the first described PLA₂ that contains 14 disulphide bonds and the first nAChR blocker possessing PLA₂ activity.

    ID:537
  28. Konshina A.G., Boldyrev I.A., Utkin Y.N., Omelkov A.V., Efremov R.G. (2011). Snake cytotoxins bind to membranes via interactions with phosphatidylserine head groups of lipids. PLoS ONE 6 (4), e19064 [+]

    The major representatives of Elapidae snake venom, cytotoxins (CTs), share similar three-fingered fold and exert diverse range of biological activities against various cell types. CT-induced cell death starts from the membrane recognition process, whose molecular details remain unclear. It is known, however, that the presence of anionic lipids in cell membranes is one of the important factors determining CT-membrane binding. In this work, we therefore investigated specific interactions between one of the most abundant of such lipids, phosphatidylserine (PS), and CT 4 of Naja kaouthia using a combined, experimental and modeling, approach. It was shown that incorporation of PS into zwitterionic liposomes greatly increased the membrane-damaging activity of CT 4 measured by the release of the liposome-entrapped calcein fluorescent dye. The CT-induced leakage rate depends on the PS concentration with a maximum at approximately 20% PS. Interestingly, the effects observed for PS were much more pronounced than those measured for another anionic lipid, sulfatide. To delineate the potential PS binding sites on CT 4 and estimate their relative affinities, a series of computer simulations was performed for the systems containing the head group of PS and different spatial models of CT 4 in aqueous solution and in an implicit membrane. This was done using an original hybrid computational protocol implementing docking, Monte Carlo and molecular dynamics simulations. As a result, at least three putative PS-binding sites with different affinities to PS molecule were delineated. Being located in different parts of the CT molecule, these anion-binding sites can potentially facilitate and modulate the multi-step process of the toxin insertion into lipid bilayers. This feature together with the diverse binding affinities of the sites to a wide variety of anionic targets on the membrane surface appears to be functionally meaningful and may adjust CT action against different types of cells.

    ID:525
  29. Alama A., Bruzzo C., Cavalieri Z., Forlani A., Utkin Y., Casciano I., Romani M. (2011). Inhibition of the nicotinic acetylcholine receptors by cobra venom α-neurotoxins: is there a perspective in lung cancer treatment? PLoS ONE 6 (6), e20695 [+]

    Nicotine exerts its oncogenic effects through the binding to nicotinic acetylcholine receptors (nAChRs) and the activation of downstream pathways that block apoptosis and promote neo-angiogenesis. The nAChRs of the α7 subtype are present on a wide variety of cancer cells and their inhibition by cobra venom neurotoxins has been proposed in several articles and reviews as a potential innovative lung cancer therapy. However, since part of the published results was recently retracted, we believe that the antitumoral activity of cobra venom neurotoxins needs to be independently re-evaluated.We determined the activity of α-neurotoxins from Naja atra (short-chain neurotoxin, α-cobrotoxin) and Naja kaouthia (long-chain neurotoxin, α-cobratoxin) in vitro by cytotoxicity measurements in 5 lung cancer cell lines, by colony formation assay with α7nAChRs expressing and non-expressing cell lines and in vivo by assessing tumor growth in an orthotopic Non-Obese Diabetic/Severe Combined Immunodeficient (NOD/SCID) mouse model system utilizing different treatment schedules and dosages.No statistically significant reduction in tumor growth was observed in the treatment arms in comparison to the control for both toxins. Paradoxically α-cobrotoxin from Naja atra showed the tendency to enhance tumor growth although, even in this case, the statistical significance was not reached.In conclusion our results show that, in contrast with other reports, the nAChR inhibitors α-cobratoxin from N. kaouthia and α-cobrotoxin from N. atra neither suppressed tumor growth nor prolonged the survival of the treated animals.

    ID:538
  30. Osipov A., Utkin Y.u. (2011). Phospholipase A2 and Signaling Pathways in Pheochromocytoma PC12 Cells. Pheochromocytoma - A New View of the Old Problem, Jose Fernando Martin (Ed.), ISBN: 978-953-307-822-9, InTech, Available from: http://www.intechopen.com/articles/show/title/phospholipase-a2-and-signaling-pathways-in-pheochromocytoma-pc12-cells , [+]

    В данной главе рассматривается роль фосфолипаз А2 в сигнальных процессах, протекающих в клетках линии РС12 феохромоцитомы крысы. Обсуждаются возможные механизмы участия фосфолипаз А2 в этих процессах и их взаимосвязь с процессами дифференцировки и гибели клеток.

    ID:632
  31. Konshina A.G., Boldyrev I.A., Omelkov A.V., Utkin Y.N., Efremov R.G. (2010). Anionic lipids: determinants of binding cytotoxins from snake venom on the surface of cell membranes. Acta Naturae 2 (2), 88–96 [+]

    The cytotoxic properties of cytotoxins (CTs) from snake venom are mediated by their interaction with the cell membrane. The hydrophobic pattern containing the tips of loops I-III and flanked by polar residues is known to be a membrane-binding motif of CTs. However, this is not enough to explain the difference in activity among various CTs which are similar in sequence and in 3D structure. The mechanism of further CT-membrane interaction leading to pore formation and cell death still remains unknown. Published experimental data on the specific interaction between CT and low molecular weight anionic components (sulphatide) of the bilayer point to the existence of corresponding ligand binding sites on the surface of toxin molecules. In this work we study the membrane-lytic properties of CT I, CT II (Naja oxiana), and Ct 4 (Naja kaouthia), which belong to different structural and functional types (P- and S-type) of CTs, by measuring the intensity of a fluorescent dye, calcein released from liposomes containing a phosphatidylserine (PS) lipid as an anionic component. Using molecular docking simulations, we find and characterize three sites in CT molecules that can potentially bind the PS polar head. Based on the data obtained, we suggest a hypothesis that CTs can specifically interact with one or more of the anionic lipids (in particular, with PS) contained in the membrane, thus facilitating the interaction between CTs and the lipid bilayer of a cell membrane.

    ID:1004
  32. Tsetlin V., Utkin Y., Kasheverov I. (2009). Polypeptide and peptide toxins, magnifying lenses for binding sites in nicotinic acetylcholine receptors. Biochem. Pharmacol. 78 (7), 720–31 [+]

    At present the cryo-electron microscopy structure at 4A resolution is known for the Torpedo marmorata nicotinic acetylcholine receptor (nAChR), and high-resolution X-ray structures have been recently determined for bacterial ligand-gated ion channels which have the same type of spatial organization. Together all these structures provide the basis for better understanding functioning of muscle-type and neuronal nAChRs, as well as of other Cys-loop receptors: 5HT3-, glycine-, GABA-A and some other. Detailed information about the ligand-binding sites in nAChRs, necessary both for understanding the receptor functioning and for rational drug design, became available when the X-ray structures were solved for the acetylcholine-binding proteins (AChBP), excellent models for the ligand-binding domains of all Cys-loop receptors. Of special value in this respect are the X-ray structures of AChBP complexes with agonists and antagonists. Among the latter are the complexes with polypeptide and peptide antagonists, that is with protein neurotoxins from snake venoms and peptide neurotoxins (alpha-conotoxins) from poisonous marine snails of Conus genus. The role of a bridge between the AChBP and nAChRs is played by the X-ray structure of the ligand-binding domain of alpha1 subunit of nAChR in the complex with alpha-bungarotoxin. The purpose of this review is to show the role of well-known and new polypeptide and peptide neurotoxins, from the earlier days of nAChRs research until present time, in identification of different nAChR subtypes and mapping their binding sites.

    ID:366
  33. Mordvintsev D.Y., Polyak Y.L., Rodionov D.I., Jakubik J., Dolezal V., Karlsson E., Tsetlin V.I., Utkin Y.N. (2009). Weak toxin WTX from Naja kaouthia cobra venom interacts with both nicotinic and muscarinic acetylcholine receptors. FEBS J. 276 (18), 5065–75 [+]

    В этой работе показано, что слабый нейротоксин WTX может взаимодействовать как с никотиновыми, так и с мускариновыми холинорецепторами. При этом в никотиновых холинорецепторах взаимодействует с ортостерическим участком связывания, а в мускариновых холинорецепторам – с аллостерическим участком.

    ID:193
  34. Osipov A.V., Filkin S.Y., Makarova Y.V., Tsetlin V.I., Utkin Y.N. (2009). A new type of thrombin inhibitor, noncytotoxic phospholipase A2, from the Naja haje cobra venom. Toxicon 55 (2-3), 186–94 [+]

    Из яда кобры Naja haje выделен новый антикоагулянтный белок, обладающий способностью ингибировать тромбин. Это – первый ингибитор тромбина, обнаруженный в яде змеи, принадлежащей семейству Elapidae. Белок представляет собой фософлипазу А2 и является первым примером ферментов этой группы, обладающим способностью ингибировать тромбин.

    ID:364
  35. Osipov A.V., Kasheverov I.E., Makarova Y.V., Starkov V.G., Vorontsova O.V., Ziganshin R.K., Andreeva T.V., Serebryakova M.V., Benoit A., Hogg R.C., Bertrand D., Tsetlin V.I., Utkin Y.N. (2008). Naturally occurring disulfide-bound dimers of three-fingered toxins: a paradigm for biological activity diversification. J. Biol. Chem. 283 (21), 14571–80 [+]

    Впервые обнаружены трех-петельные токсины нового структурного типа: соединенные дисульфидами димеры кобратоксина с цитотоксинами, а также гомодимер кобратоксина. Показано, что в результате димеризации кобратоксин приобретает способность взаимодействовать с еще одним типом никотинового холинорецептора. Такая пост-трансляционная модификация может рассматриваться как еще один путь диверсификации биологической активности трех-петельных токсинов.

    ID:105
  36. Ramazanova A.S., Zavada L.L., Starkov V.G., Kovyazina I.V., Subbotina T.F., Kostyukhina E.E., Dementieva I.N., Ovchinnikova T.V., Utkin Y.N. (2008). Heterodimeric neurotoxic phospholipases A2--the first proteins from venom of recently established species Vipera nikolskii: implication of venom composition in viper systematics. Toxicon 51 (4), 524–37 [+]

    For the first time the venom of recently established viper species Vipera nikolskii was fractionated and two heterodimeric phospholipases A(2) (HDP-1 and HDP-2) were isolated. Isolation of HDP-1 and HDP-2 is the first indication of the presence of two heterodimeric phospholipases A(2) in the venom of one viper species. When tested on the frog neuromuscular junction, isolated proteins affected neuromuscular transmission acting presynaptically. Using RP-HPLC, each heterodimer was separated into two monomeric subunits: basic phospholipase A(2) (HDP-1P and HDP-2P) and acidic component without enzymatic activity (HDP-In). The complete primary structures of subunits were deduced from corresponding sequences of cDNAs. The determined amino acid sequences were homologous to those of vipoxin from Vipera ammodytes and vaspin from Vipera aspis. Similar proteins were not found earlier in the well-studied venom of Vipera berus, the species from which V. nikolskii was recently separated. Our finding supports at the biochemical level the correctness of the establishment of V. nikolskii as an independent species. The finding of similar proteins (HDPs and vipoxin) in geographically remote species (V. nikolskii and V. ammodytes) corroborates the hypothesis about the pre-existence of genes encoding these proteins in all true viper species and their expression under certain conditions.

    ID:413
  37. Lyukmanova E.N., Shenkarev Z.O., Schulga A.A., Ermolyuk Y.S., Mordvintsev D.Y., Utkin Y.N., Shoulepko M.A., Hogg R.C., Bertrand D., Dolgikh D.A., Tsetlin V.I., Kirpichnikov M.P. (2007). Bacterial expression, NMR, and electrophysiology analysis of chimeric short/long-chain alpha-neurotoxins acting on neuronal nicotinic receptors. J. Biol. Chem. 282 (34), 24784–91 [+]

    Different snake venom neurotoxins block distinct subtypes of nicotinic acetylcholine receptors (nAChR). Short-chain alpha-neurotoxins preferentially inhibit muscle-type nAChRs, whereas long-chain alpha-neurotoxins block both muscle-type and alpha7 homooligomeric neuronal nAChRs. An additional disulfide in the central loop of alpha- and kappa-neurotoxins is essential for their action on the alpha7 and alpha3beta2 nAChRs, respectively. Design of novel toxins may help to better understand their subtype specificity. To address this problem, two chimeric toxins were produced by bacterial expression, a short-chain neurotoxin II Naja oxiana with the grafted disulfide-containing loop from long-chain neurotoxin I from N. oxiana, while a second chimera contained an additional A29K mutation, the most pronounced difference in the central loop tip between long-chain alpha-neurotoxins and kappa-neurotoxins. The correct folding and structural stability for both chimeras were shown by (1)H and (1)H-(15)N NMR spectroscopy. Electrophysiology experiments on the nAChRs expressed in Xenopus oocytes revealed that the first chimera and neurotoxin I blockalpha7 nAChRs with similar potency (IC(50) 6.1 and 34 nM, respectively). Therefore, the disulfide-confined loop endows neurotoxin II with full activity of long-chain alpha-neurotoxin and the C-terminal tail in neurotoxin I is not essential for binding. The A29K mutation of the chimera considerably diminished the affinity for alpha7 nAChR (IC(50) 126 nM) but did not convey activity at alpha3beta2 nAChRs. Docking of both chimeras toalpha7 andalpha3beta2 nAChRs was possible, but complexes with the latter were not stable at molecular dynamics simulations. Apparently, some other residues and dimeric organization of kappa-neurotoxins underlie their selectivity for alpha3beta2 nAChRs.

    ID:357
  38. Mordvitsev D.Y., Polyak Y.L., Kuzmin D.A., Levtsova O.V., Tourleigh Y.V., Utkin Y.N., Shaitan K.V., Tsetlin V.I. (2007). Computer modeling of binding of diverse weak toxins to nicotinic acetylcholine receptors. Comput Biol Chem 31 (2), 72–81 [+]

    Weak toxins are the "three-fingered" snake venoms toxins grouped together by having an additional disulfide in the N-terminal loop I. In general, weak toxins have low toxicity, and biological targets have been identified for some of them only, recently by detecting the effects on the nicotinic acetylcholine receptors (nAChR). Here the methods of docking and molecular dynamics simulations are used for comparative modeling of the complexes between four weak toxins of known spatial structure (WTX, candoxin, bucandin, gamma-bungarotoxin) and nAChRs. WTX and candoxin are those toxins whose blocking of the neuronal alpha7- and muscle-type nAChR has been earlier shown in binding assays and electrophysiological experiments, while for the other two toxins no such activity has been reported. Only candoxin and WTX are found here to give stable solutions for the toxin-nAChR complexes. These toxins appear to approach the binding site similarly to short alpha-neurotoxins, but their final position resembles that of alpha-cobratoxin, a long alpha-neurotoxin, in the complex with the acetylcholine-binding protein. The final spatial structures of candoxin and WTX complexes with the alpha7 neuronal or muscle-type nAChR are very similar and do not provide immediate answer why candoxin has a much higher affinity than WTX, but both of them share a virtually irreversible mode of binding to one or both these nAChR subtypes. Possible explanation comes from docking and MD simulations which predict fast kinetics of candoxin association with nAChR, no gross changes in the toxin conformation (with smaller toxin flexibility on alpha7 nAChR), while slow WTX binding to nAChR is associated with slow irreversible rearrangement both of the tip of the toxin loop II and of the binding pocket residues locking finally the toxin molecule. Computer modeling showed that the additional disulfide in the loop I is not directly involved in receptor binding of WTX and candoxin, but it stabilizes the structure of loop I which plays an important role in toxin delivery to the binding site. In summary, computer modeling visualized possible modes of binding for those weak toxins which interact with the nAChR, provided no solutions for those weak toxins whose targets are not the nAChRs, and demonstrated that the additional disulfide in loop I cannot be a sound criteria for joining all weak toxins into one group; the conclusion about the diversity of weak toxins made from computer modeling is in accord with the earlier phylogenetic analysis.

    ID:344
  39. Utkin Y.N., Osipov A.V. (2007). Non-lethal polypeptide components in cobra venom. Curr. Pharm. Des. 13 (28), 2906–15 [+]

    Яды кобр содержат целый ряд низкотоксичных компонентов, которые принадлежвт к различным структурным ифункциональным типам. Их роль в поражающем действии яда не всегда ясна. Представленный обзор является первой попыткой систематизировать данные о низкотоксичных компонентах ядов кобр.

    ID:367
  40. Mordvintsev D.Y., Polyak Y.L., Levtsova O.V., Tourleigh Y.V., Kasheverov I.E., Shaitan K.V., Utkin Y.N., Tsetlin V.I. (2005). A model for short alpha-neurotoxin bound to nicotinic acetylcholine receptor from Torpedo californica: comparison with long-chain alpha-neurotoxins and alpha-conotoxins. Comput Biol Chem 29 (6), 398–411 [+]

    Short-chain alpha-neurotoxins from snakes are highly selective antagonists of the muscle-type nicotinic acetylcholine receptors (nAChR). Although their spatial structures are known and abundant information on topology of binding to nAChR is obtained by labeling and mutagenesis studies, the accurate structure of the complex is not yet known. Here, we present a model for a short alpha-neurotoxin, neurotoxin II from Naja oxiana (NTII), bound to Torpedo californica nAChR. It was built by comparative modeling, docking and molecular dynamics using 1H NMR structure of NTII, cross-linking and mutagenesis data, cryoelectron microscopy structure of Torpedo marmorata nAChR [Unwin, N., 2005. Refined structure of the nicotinic acetylcholine receptor at 4A resolution. J. Mol. Biol. 346, 967-989] and X-ray structures of acetylcholine-binding protein (AChBP) with agonists [Celie, P.H., van Rossum-Fikkert, S.E., van Dijk, W.J., Brejc, K., Smit, A.B., Sixma, T.K., 2004. Nicotine and carbamylcholine binding to nicotinic acetylcholine receptors as studied in AChBP crystal structures. Neuron 41 (6), 907-914] and antagonists: alpha-cobratoxin, a long-chain alpha-neurotoxin [Bourne, Y., Talley, T.T., Hansen, S.B., Taylor, P., Marchot, P., 2005. Crystal structure of Cbtx-AChBP complex reveals essential interactions between snake alpha-neurotoxins and nicotinic receptors. EMBO J. 24 (8), 1512-1522] and alpha-conotoxin [Celie, P.H., Kasheverov, I.E., Mordvintsev, D.Y., Hogg, R.C., van Nierop, P., van Elk, R., van Rossum-Fikkert, S.E., Zhmak, M.N., Bertrand, D., Tsetlin, V., Sixma, T.K., Smit, A.B., 2005. Crystal structure of nicotinic acetylcholine receptor homolog AChBP in complex with an alpha-conotoxin PnIA variant. Nat. Struct. Mol. Biol. 12 (7), 582-588]. In complex with the receptor, NTII was located at about 30 A from the membrane surface, the tip of its loop II plunges into the ligand-binding pocket between the alpha/gamma or alpha/delta nAChR subunits, while the loops I and III contact nAChR by their tips only in a 'surface-touch' manner. The toxin structure undergoes some changes during the final complex formation (for 1.45 rmsd in 15-25 ps according to AMBER'99 molecular dynamics simulation), which correlates with NMR data. The data on the mobility and accessibility of spin- and fluorescence labels in free and bound NTII were used in MD simulations. The binding process is dependent on spontaneous outward movement of the C-loop earlier found in the AChBP complexes with alpha-cobratoxin and alpha-conotoxin. Among common features in binding of short- and long alpha-neurotoxins is the rearrangement of aromatic residues in the binding pocket not observed for alpha-conotoxin binding. Being in general very similar, the binding modes of short- and long alpha-neurotoxins differ in the ways of loop II entry into nAChR.

    ID:1086
  41. Feofanov A.V., Sharonov G.V., Astapova M.V., Rodionov D.I., Utkin Y.N., Arseniev A.S. (2005). Cancer cell injury by cytotoxins from cobra venom is mediated through lysosomal damage. Biochem. J. 390 (Pt 1), 11–8 [+]

    Статья посвящена исследованию механизмов цитотоксического действия цитотоксинов (ЦТ) из яда кобр. В данной работе показано, что ЦТ 1 и 2 из яда кобры Naja oxiana, ЦТ 1 из Naja haje и ЦТ 3 из Naja kaouthia способны накапливаться в лизосомах клеток промиелоцитарной лейкемии человека HL60 и аденокарциномы легкого человека A549. Кинетика и концентрационная зависимость накопления ЦТ в лизосомах согласуется с кинетикой и концентрационной зависимостью гибели клеток, что свидетельствует о том, что лизосомы могут быть одной из мишеней ЦТ, а воздействие на эту мишень заключается в концентрационно-зависимой пермеабилизации мембраны лизосом.

    ID:93
  42. Dubovskii P.V., Lesovoy D.M., Dubinnyi M.A., Konshina A.G., Utkin Y.N., Efremov R.G., Arseniev A.S. (2005). Interaction of three-finger toxins with phospholipid membranes: comparison of S- and P-type cytotoxins. Biochem. J. 387 (Pt 3), 807–15 [+]

    The CTs (cytotoxins) I and II are positively charged three-finger folded proteins from venom of Naja oxiana (the Central Asian cobra). They belong to S- and P-type respectively based on Ser-28 and Pro-30 residues within a putative phospholipid bilayer binding site. Previously, we investigated the interaction of CTII with multilamellar liposomes of dipalmitoylphosphatidylglycerol by wide-line (31)P-NMR spectroscopy. To compare interactions of these proteins with phospholipids, we investigated the interaction of CTI with the multilamellar liposomes of dipalmitoylphosphatidylglycerol analogously. The effect of CTI on the chemical shielding anisotropy and deformation of the liposomes in the magnetic field was determined at different temperatures and lipid/protein ratios. It was found that both the proteins do not affect lipid organization in the gel state. In the liquid crystalline state of the bilayer they disturb lipid packing. To get insight into the interactions of the toxins with membranes, Monte Carlo simulations of CTI and CTII in the presence of the bilayer membrane were performed. It was found that both the toxins penetrate into the bilayer with the tips of all the three loops. However, the free-energy gain on membrane insertion of CTI is smaller (by approximately 7 kcal/mol; 1 kcal identical with 4.184 kJ) when compared with CTII, because of the lower hydrophobicity of the membrane-binding site of CTI. These results clearly demonstrate that the P-type cytotoxins interact with membranes stronger than those of the S-type, although the mode of the membrane insertion is similar for both the types.

    ID:970
  43. Osipov A.V., Astapova M.V., Tsetlin V.I., Utkin Y.N. (2004). The first representative of glycosylated three-fingered toxins. Cytotoxin from the Naja kaouthia cobra venom. Eur. J. Biochem. 271 (10), 2018–27 [+]

    В этой работе впервые был описан гликозилированный цитотоксин, выделенный из яда кобры Naja kaouthia. Это первый представитель обширного семейства трех-петельных токсинов, для которого обнаружена пост-трансляционная модификация

    ID:192
  44. Utkin Y.N., Kukhtina V.V., Kryukova E.V., Chiodini F., Bertrand D., Methfessel C., Tsetlin V.I. (2001). "Weak toxin" from Naja kaouthia is a nontoxic antagonist of alpha 7 and muscle-type nicotinic acetylcholine receptors. J. Biol. Chem. 276 (19), 15810–5 [+]

    Эта работа показала, что давно известные «слабые» токсины способны взаимодействовать с никотиновыми холинорецепторами. При этом, обладая слабым сродством к рецептору, такие токсины связываются практически необратимо.

    ID:103
  45. Machold J., Utkin Y., Kirsch D., Kaufmann R., Tsetlin V., Hucho F. (1995). Photolabeling reveals the proximity of the alpha-neurotoxin binding site to the M2 helix of the ion channel in the nicotinic acetylcholine receptor. Proc. Natl. Acad. Sci. U.S.A. 92 (16), 7282–6 [+]

    Впервые локализован аминокислотный остаток холинорецептора, меченный фотоактивированным производным нейротоксина. Это позволило установить расположение молекулы токсина на рецепторе. Согласно полученным данным молекула токсина находится гораздо ближе к поверхности мембраны, чем считалось ранее.

    ID:102
  46. Kreienkamp H.J., Utkin Y.N., Weise C., Machold J., Tsetlin V.I., Hucho F. (1992). Investigation of ligand-binding sites of the acetylcholine receptor using photoactivatable derivatives of neurotoxin II from Naja naja oxiana. Biochemistry 31 (35), 8239–44 [+]

    В данной работе впервые с использованием фотоактивируемых производных нейротоксина установлено, какие субъединицы холинорецептора мышечного типа участвуют в формировании участка связывания агонистов/конкурентных антагонистов.

    ID:101