Козлов Сергей Александрович
Доктор химических наук
Руководитель подразделения (Лаборатория нейрорецепторов и нейрорегуляторов)
Тел.:
Эл. почта: serg@ibch.ru
Избранные публикации
- (2018). New APETx-like peptides from sea anemone Heteractis crispa modulate ASIC1a channels. Peptides 104, 41–49
[+]Sea anemones are an abundant source of various biologically active peptides. The hydrophobic 20% ethanol fraction of tropical sea anemone Heteractis crispa was shown to contain at least 159 peptide compounds including neurotoxins, proteinase and α-amylase inhibitors, as well as modulators of acid-sensing ion channels (ASICs). The three new peptides, π-AnmTX Hcr 1b-2, -3, and -4 (41 aa) (short names Hcr 1b-2, -3, -4), identified by a combination of reversed-phase liquid chromatography and mass spectrometry were found to belong to the class 1b sea anemone neurotoxins. The amino acid sequences of these peptides were determined by Edman degradation and tandem mass spectrometry. The percent of identity of Hcr 1b-2, -3, and -4 with well-known ASIC3 inhibitors Hcr 1b-1 from H. crispa and APETx2 from Anthopleura elegantissima is 95-78% and 46-49%, respectively. Electrophysiological experiments on homomeric ASIC channels expressed in Xenopus laevis oocytes establish that these peptides are the first inhibitors of ASIC1a derived from sea anemone venom. The major peptide, Hcr 1b-2, inhibited both rASIC1a (IC 4.8 ± 0.3 μM; nH 0.92 ± 0.05) and rASIC3 (IC 15.9 ± 1.1 μM; nH 1.0 ± 0.05). The maximum inhibition at saturating peptide concentrations reached 64% and 81%, respectively. In the model of acid-induced muscle pain Hcr 1b-2 was also shown to exhibit an antihyperalgesic effect, significantly reducing of the pain threshold of experimental animals.
ID:2081 - (2018). Structural variability of DNA-containing Mg-pyrophosphate microparticles: optimized conditions to produce particles with desired size and morphology. J. Biomol. Struct. Dyn. , 1–13 [+]
Our previous studies demonstrated the formation of structurally diverse DNA-containing microparticles (DNA MPs) in PCR with Mg-pyrophosphate (MgPPi) as the structure-forming component. These DNA MPs were referred to major structural types: microdisks (2D MPs) with nanometer thickness and 3D MPs with sophisticated morphology and constructed from intersecting disks and their segments. Little is known about factors that influence both the morphology and size of DNA MPs, and the present study was aimed at fulfilling this gap. We showed that the addition of Mn cations to PCR mixtures caused the profound changes in MPs morphology, depending on DNA polymerase used (KlenTaq or Taq). Asymmetric PCR with 20-fold decrease in the concentration of one of two primers facilitated the predominant formation of microdisks with unusual structure. The addition of 1 mM Na-pyrophosphate to PCR mixtures with synthesized DNA and subsequent thermal cycling (10-15 cycles) were optimal to produce microdisks or nanometer 3D particles. Using electron microscopy, we studied also the structure of inorganic micro- and nanoparticles from MgPPi, formed during multiple heating and cooling cycles of a mixture of Mg and Na-pyrophosphate in various regimes. Also, we found the conditions to yield planar (Mg·Mn)PPi nanocrystals (diameter ~100 nm and thickness ~10 nm) which efficiently adsorbed exogenous DNA. These inorganic nanoparticles are promising for DNA delivery in transfection studies. Mechanisms to be involved in structural modifications of MPs and perspectives of their practical application are discussed.
ID:2082 - (2018). Proton-independent activation of acid-sensing ion channel 3 by an alkaloid, lindoldhamine, from Laurus nobilis. Br. J. Pharmacol. 175 (6), 924–937 [+]
Acid-sensing ion channels (ASICs) play an important role in synaptic plasticity and learning, as well as in nociception and mechanosensation. ASICs are involved in pain and in neurological and psychiatric diseases, but their therapeutic potential is limited by the lack of ligands activating them at physiological pH.
ID:2083 - (2017). Identification of unusual peptides with new Cys frameworks in the venom of the cold-water sea anemone Cnidopus japonicus. Sci Rep 7 (1), 14534 [+]
Sea anemones (Actiniaria) are intensely popular objects of study in venomics. Order Actiniaria includes more than 1,000 species, thus presenting almost unlimited opportunities for the discovery of novel biologically active molecules. The venoms of cold-water sea anemones are studied far less than the venoms of tropical sea anemones. In this work, we analysed the molecular venom composition of the cold-water sea anemone Cnidopus japonicus. Two sets of NGS data from two species revealed molecules belonging to a variety of structural classes, including neurotoxins, toxin-like molecules, linear polypeptides (Cys-free), enzymes, and cytolytics. High-throughput proteomic analyses identified 27 compounds that were present in the venoms. Some of the toxin-like polypeptides exhibited novel Cys frameworks. To characterise their function in the venom, we heterologously expressed 3 polypeptides with unusual Cys frameworks (designated CjTL7, CjTL8, and AnmTx Cj 1c-1) in E. coli. Toxicity tests revealed that the CjTL8 polypeptide displays strong crustacean-specific toxicity, while AnmTx Cj 1c-1 is toxic to both crustaceans and insects. Thus, an improved NGS data analysis algorithm assisted in the identification of toxins with unusual Cys frameworks showing no homology according to BLAST. Our study shows the advantage of combining omics analysis with functional tests for active polypeptide discovery.
ID:1908 - (2017). Animal toxins for channelopathy treatment. Neuropharmacology , [+]
Ion channels are transmembrane proteins that allow passive flow of ions inside and/or outside of cells or cell organelles. Except mutations lead to nonfunctional protein production or abolished receptor entrance on the membrane surface an altered channel may have two principal conditions that can be corrected. The channel may conduct fewer ions through (loss-of-function mutations) or too many ions (gain-of-function mutations) compared to a normal channel. Toxins from animal venoms are specialised molecules that are generally oriented toward interactions with ion channels. This is a result of long coevolution between predators and their prey. On the molecular level, toxins activate or inhibit ion channels, so they are ideal molecules for restoring conductance in mutated channels. Another aspect of this long coevolution is that a broad variety of toxins have been fine tuned to recognize the channels of different species, keeping many amino acids substitution among sequences. Many peptide ligands with high selectivity to specific receptor subtypes have been isolated from animal venoms, some of which are absolutely non-toxic to humans and mammalians. It is expected that molecules that are selective to each known receptor can be found in animal venoms, but the pool of toxins currently does not override all receptors described as being involved in channelopathies. Modern investigating methods have enhanced the search process for selective ligands. One prominent method is a site-directed mutagenesis of existing toxins to change the selectivity or/and affinity to the selected receptor, which has shown positive results.
ID:1927 - (2017). New Disulfide-Stabilized Fold Provides Sea Anemone Peptide to Exhibit Both Antimicrobial and TRPA1 Potentiating Properties. Toxins (Basel) 9 (5), [+]
A novel bioactive peptide named τ-AnmTx Ueq 12-1 (short name Ueq 12-1) was isolated and characterized from the sea anemone Urticina eques. Ueq 12-1 is unique among the variety of known sea anemone peptides in terms of its primary and spatial structure. It consists of 45 amino acids including 10 cysteine residues with an unusual distribution and represents a new group of sea anemone peptides. The 3D structure of Ueq 12-1, determined by NMR spectroscopy, represents a new disulfide-stabilized fold partly similar to the defensin-like fold. Ueq 12-1 showed the dual activity of both a moderate antibacterial activity against Gram-positive bacteria and a potentiating activity on the transient receptor potential ankyrin 1 (TRPA1). Ueq 12-1 is a unique peptide potentiator of the TRPA1 receptor that produces analgesic and anti-inflammatory effects in vivo. The antinociceptive properties allow us to consider Ueq 12-1 as a potential analgesic drug lead with antibacterial properties.
ID:1914 - (2017). Marine Cyclic Guanidine Alkaloids Monanchomycalin B and Urupocidin A Act as Inhibitors of TRPV1, TRPV2 and TRPV3, but not TRPA1 Receptors. Mar Drugs 15 (4), [+]
Marine sponges contain a variety of low-molecular-weight compounds including guanidine alkaloids possessing different biological activities. Monanchomycalin B and urupocidin A were isolated from the marine sponge Monanchora pulchra. We found that they act as inhibitors of the TRPV1, TRPV2, and TRPV3 channels, but are inactive against the TRPA1 receptor. Monanchomycalin B is the most active among all published marine alkaloids (EC50 6.02, 2.84, and 3.25 μM for TRPV1, TRPV2, and TRPV3, correspondingly). Moreover, monanchomycalin B and urupocidin A are the first samples of marine alkaloids affecting the TRPV2 receptor. Two semi-synthetic urupocidin A derivatives were also obtained and tested against TRP (Transient Receptor Potential) receptors that allowed us to collect some data concerning the structure-activity relationship in this series of compounds. We showed that the removal of one of three side chains or double bonds in the other side chains in urupocidin A led to a decrease of the inhibitory activities. New ligands specific to the TRPV subfamily may be useful for the design of medicines as in the study of TRP channels biology.
ID:1929 - (2017). Peptide from Sea Anemone Metridium senile Affects Transient Receptor Potential Ankyrin-repeat 1 (TRPA1) Function and Produces Analgesic Effect. J. Biol. Chem. 292 (7), 2992–3004 [+]
The transient receptor potential ankyrin-repeat 1 (TRPA1) is an important player in pain and inflammatory pathways. It is a promising target for novel drug development for the treatment of a number of pathological states. A novel peptide producing a significant potentiating effect on allyl isothiocyanate- and diclofenac-induced currents of TRPA1 was isolated from the venom of sea anemone Metridium senile. It is a 35-amino acid peptide cross-linked by two disulfide bridges named τ-AnmTX Ms 9a-1 (short name Ms 9a-1) according to a structure similar to other sea anemone peptides belonging to structural group 9a. The structures of the two genes encoding the different precursor proteins of Ms 9a-1 were determined. Peptide Ms 9a-1 acted as a positive modulator of TRPA1 in vitro but did not cause pain or thermal hyperalgesia when injected into the hind paw of mice. Intravenous injection of Ms 9a-1 (0.3 mg/kg) produced a significant decrease in the nociceptive and inflammatory response to allyl isothiocyanate (the agonist of TRPA1) and reversed CFA (Complete Freund's Adjuvant)-induced inflammation and thermal hyperalgesia. Taken together these data support the hypothesis that Ms 9a-1 potentiates the response of TRPA1 to endogenous agonists followed by persistent functional loss of TRPA1-expressing neurons. We can conclude that TRPA1 potentiating may be useful as a therapeutic approach as Ms 9a-1 produces significant analgesic and anti-inflammatory effects in mice models of pain.
ID:1928 - (2017). TRPV1 activation power can switch an action mode for its polypeptide ligands. PLoS ONE 12 (5), e0177077 [+]
TRPV1 (vanilloid) receptors are activated by different types of stimuli including capsaicin, acidification and heat. Various ligands demonstrate stimulus-dependent action on TRPV1. In the present work we studied the action of polypeptides isolated from sea anemone Heteractis crispa (APHC1, APHC2 and APHC3) on rat TRPV1 receptors stably expressed in CHO cells using electrophysiological recordings, fluorescent Ca2+ measurements and molecular modeling. The APHCs potentiated TRPV1 responses to low (3-300 nM) concentrations of capsaicin but inhibited responses to high (>3.0 μM) concentrations. The activity-dependent action was also found for TRPV1 responses to 2APB and acidification. Thus the action mode of APHCs is bimodal and depended on the activation stimuli strength-potentiation of low-amplitude responses and no effect/inhibition of high-amplitude responses. The double-gate model of TRPV1 activation suggests that APHC-polypeptides may stabilize an intermediate state during the receptor activation. Molecular modeling revealed putative binding site at the outer loops of TRPV1. Binding to this site can directly affect activation by protons and can be allosterically coupled with capsaicin site. The results are important for further investigations of both TRPV1 and its ligands for potential therapeutic use.
ID:1930 - (2017). Endogenous Isoquinoline Alkaloids Agonists of Acid-Sensing Ion Channel Type 3. Front Mol Neurosci 10, 282 [+]
Acid-sensing ion channels (ASICs) ASIC3 expressed mainly in peripheral sensory neurons play an important role in pain perception and inflammation development. In response to acidic stimuli, they can generate a unique biphasic current. At physiological pH 7.4, human ASIC3 isoform (hASIC3) is desensitized and able to generate only a sustained current. We found endogenous isoquinoline alkaloids (EIAs), which restore hASIC3 from desensitization and recover the transient component of the current. Similarly, rat ASIC3 isoform (rASIC3) can also be restored from desensitization (at pH < 7.0) by EIAs with the same potency. At physiological pH and above, EIAs at high concentrations were able to effectively activate hASIC3 and rASIC3. Thus, we found first endogenous agonists of ASIC3 channels that could both activate and prevent or reverse desensitization of the channel. The decrease of EIA levels could be suggested as a novel therapeutic strategy for treatment of pain and inflammation.
ID:1932 - (2015). Conversed mutagenesis of an inactive peptide to ASIC3 inhibitor for active sites determination. Toxicon , [+]
Peptide Ugr9-1 from the venom of sea anemone Urticina grebelnyi selectively inhibits the ASIC3 channel and significantly reverses inflammatory and acid-induced pain in vivo. A close homolog peptide Ugr 9-2 does not have these features. To find the pharmacophore residues and explore structure-activity relationships of Ugr 9-1, we performed site-directed mutagenesis of Ugr 9-2 and replaced several positions by the corresponding residues from Ugr 9-1. Mutant peptides Ugr 9-2 T9F and Ugr 9-2 Y12H were able to inhibit currents of the ASIC3 channels 2.2 times and 1.3 times weaker than Ugr 9-1, respectively. Detailed analysis of the spatial models of Ugr 9-1, Ugr 9-2 and both mutant peptides revealed the presence of the basic-aromatic clusters on opposite sides of the molecule, each of which is responsible for the activity. Additionally, Ugr9-1 mutant with truncated N- and C-termini retained similar with the Ugr9-1 action in vitro and was equally potent in vivo model of thermal hypersensitivity. All together, these results are important for studying the structure-activity relationships of ligand-receptor interaction and for the future development of peptide drugs from animal toxins.
ID:1472 - (2015). Latarcins: versatile spider venom peptides. Cell. Mol. Life Sci. 72 (23), 4501–22
[+]Arthropod venoms feature the presence of cytolytic peptides believed to act synergetically with neurotoxins to paralyze prey or deter aggressors. Many of them are linear, i.e., lack disulfide bonds. When isolated from the venom, or obtained by other means, these peptides exhibit common properties. They are cationic; being mostly disordered in aqueous solution, assume amphiphilic α-helical structure in contact with lipid membranes; and exhibit general cytotoxicity, including antifungal, antimicrobial, hemolytic, and anticancer activities. To suit the pharmacological needs, the activity spectrum of these peptides should be modified by rational engineering. As an example, we provide a detailed review on latarcins (Ltc), linear cytolytic peptides from Lachesana tarabaevi spider venom. Diverse experimental and computational techniques were used to investigate the spatial structure of Ltc in membrane-mimicking environments and their effects on model lipid bilayers. The antibacterial activity of Ltc was studied against a panel of Gram-negative and Gram-positive bacteria. In addition, the action of Ltc on erythrocytes and cancer cells was investigated in detail with confocal laser scanning microscopy. In the present review, we give a critical account of the progress in the research of Ltc. We explore the relationship between Ltc structure and their biological activity and derive molecular characteristics, which can be used for optimization of other linear peptides. Current applications of Ltc and prospective use of similar membrane-active peptides are outlined.
ID:1395 - (2015). Novel proline-hydroxyproline glycopeptides from the dandelion (Taraxacum officinale Wigg.) flowers: de novo sequencing and biological activity. Plant Sci. 238, 323–9 [+]
Two novel homologous peptides named ToHyp1 and ToHyp2 that show no similarity to any known proteins were isolated from Taraxacum officinale Wigg. flowers by multidimensional liquid chromatography. Amino acid and mass spectrometry analyses demonstrated that the peptides have unusual structure: they are cysteine-free, proline-hydroxyproline-rich and post-translationally glycosylated by pentoses, with 5 carbohydrates in ToHyp2 and 10 in ToHyp1. The ToHyp2 peptide with a monoisotopic molecular mass of 4350.3Da was completely sequenced by a combination of Edman degradation and de novo sequencing via top down multistage collision induced dissociation (CID) and higher energy dissociation (HCD) tandem mass spectrometry (MS(n)). ToHyp2 consists of 35 amino acids, contains eighteen proline residues, of which 8 prolines are hydroxylated. The peptide displays antifungal activity and inhibits growth of Gram-positive and Gram-negative bacteria. We further showed that carbohydrate moieties have no significant impact on the peptide structure, but are important for antifungal activity although not absolutely necessary. The deglycosylated ToHyp2 peptide was less active against the susceptible fungus Bipolaris sorokiniana than the native peptide. Unique structural features of the ToHyp2 peptide place it into a new family of plant defense peptides. The discovery of ToHyp peptides in T. officinale flowers expands the repertoire of molecules of plant origin with practical applications.
ID:1474 - (2015). Структурные особенности цистеин-богатых полипептидов из ядов морских анемон. Биоорг. хим. 41 (5), 511–523 [+]В обзоре рассмотрены известные полипептидные токсины из ядов морских анемон, в первую очередь, с учетом их классификации по структурным признакам. Внутрикаждого класса проанализированы наиболее яркие функциональные особенности этих полипептидов.ID:1316
- (2015). ω-Tbo-IT1-New Inhibitor of Insect Calcium Channels Isolated from Spider Venom. Sci Rep 5, 17232 [+]
Novel disulfide-containing polypeptide toxin was discovered in the venom of the Tibellus oblongus spider. We report on isolation, spatial structure determination and electrophysiological characterization of this 41-residue toxin, called ω-Tbo-IT1. It has an insect-toxic effect with LD50 19 μg/g in experiments on house fly Musca domestica larvae and with LD50 20 μg/g on juvenile Gromphadorhina portentosa cockroaches. Electrophysiological experiments revealed a reversible inhibition of evoked excitatory postsynaptic currents in blow fly Calliphora vicina neuromuscular junctions, while parameters of spontaneous ones were not affected. The inhibition was concentration dependent, with IC50 value 40 ± 10 nM and Hill coefficient 3.4 ± 0.3. The toxin did not affect frog neuromuscular junctions or glutamatergic and GABAergic transmission in rat brains. Ca(2+) currents in Calliphora vicina muscle were not inhibited, whereas in Periplaneta americana cockroach neurons at least one type of voltage gated Ca(2+) current was inhibited by ω-Tbo-IT1. Thus, the toxin apparently acts as an inhibitor of presynaptic insect Ca(2+) channels. Spatial structure analysis of the recombinant ω-Tbo-IT1 by NMR spectroscopy in aqueous solution revealed that the toxin comprises the conventional ICK fold containing an extended β-hairpin loop and short β-hairpin loop which are capable of making "scissors-like mutual motions".
ID:1341 - (2014). Linear antimicrobial peptides from Ectatomma quadridens ant venom. Biochimie 107 Pt B, 211–5 [+]
Venoms from three poneromorph ant species (Paraponera clavata, Ectatomma quadridens and Ectatomma tuberculatum) were investigated for the growth inhibition of Gram-positive and Gram-negative bacteria. It was shown that the venom of E. quadridens and its peptide fraction in particular possess marked antibacterial action. Three linear antimicrobial peptides sharing low similarity to the well-known ponericin peptides were isolated from this ant venom by means of size-exclusion and reversed-phase chromatography. The peptides showed antimicrobial activity at low micromolar concentrations. Their primary structure was established by direct Edman sequencing in combination with mass spectrometry. The most active peptide designated ponericin-Q42 was chemically synthesized. Its secondary structure was investigated in aqueous and membrane-mimicking environment, and the peptide was shown to be partially helical already in water, which is unusual for short linear peptides. Analysis of its activity on different bacterial strains, human erythrocytes and chronic myelogenous leukemia K562 cells revealed that the peptide shows broad spectrum cytolytic activity at micromolar and submicromolar concentrations. Ponericin-Q42 also possesses weak toxic activity on flesh fly larvae with LD50 of ∼105 μg/g.
ID:1150 - (2013). Spider toxins comprising disulfide-rich and linear amphipathic domains: a new class of molecules identified in the lynx spider Oxyopes takobius. FEBS J. 280 (23), 6247–61 [+]
In addition to the conventional neurotoxins and cytotoxins, venom of the lynx spider Oxyopes takobius was found to contain two-domain modular toxins named spiderines: OtTx1a, 1b, 2a and 2b. These toxins show both insecticidal activity (a median lethal dose against flesh fly larvae of 75 μg·g(-1) ) and potent antimicrobial effects (minimal inhibitory concentrations in the range 0.1-10 μm). Full sequences of the purified spiderines were established by a combination of Edman degradation, mass spectrometry and cDNA cloning. They are relatively large molecules (~ 110 residues, 12.0-12.5 kDa) and consist of two distinct modules separated by a short linker. The N-terminal part (~ 40 residues) contains no cysteine residues, is highly cationic, forms amphipathic α-helical structures in a membrane-mimicking environment, and shows potent cytolytic effects on cells of various origins. The C-terminal part (~ 60 residues) is disulfide-rich (five S-S bonds), and contains the inhibitor cystine knot (ICK/knottin) signature. The N-terminal part of spiderines is very similar to linear cytotoxic peptides found in various organisms, whereas the C-terminal part corresponds to the usual spider neurotoxins. We synthesized the modules of OtTx1a and compared their activity to that of full-length mature toxin produced recombinantly, highlighting the importance of the N-terminal part, which retained full-length toxin activity in both insecticidal and antimicrobial assays. The unique structure of spiderines completes the range of two-domain spider toxins.
ID:980 - (2013). Sea Anemone Peptide with Uncommon β-Hairpin Structure Inhibits Acid-sensing Ion Channel 3 (ASIC3) and Reveals Analgesic Activity. J. Biol. Chem. 288 (32), 23116–27 [+]
Three novel peptides were isolated from the venom of the sea anemone Urticina grebelnyi. All of them are 29 amino acid peptides cross-linked by two disulfide bridges, with a primary structure similar to other sea anemone peptides belonging to structural group 9a. The structure of the gene encoding the shared precursor protein of the identified peptides was determined. One peptide, π-AnmTX Ugr 9a-1 (short name Ugr 9-1), produced a reversible inhibition effect on both the transient and the sustained current of human ASIC3 channels expressed in Xenopus laevis oocytes. It completely blocked the transient component (IC50 10 ± 0.6 μm) and partially (48 ± 2%) inhibited the amplitude of the sustained component (IC50 1.44 ± 0.19 μm). Using in vivo tests in mice, Ugr 9-1 significantly reversed inflammatory and acid-induced pain. The other two novel peptides, AnmTX Ugr 9a-2 (Ugr 9-2) and AnmTX Ugr 9a-3 (Ugr 9-3), did not inhibit the ASIC3 current. NMR spectroscopy revealed that Ugr 9-1 has an uncommon spatial structure, stabilized by two S-S bridges, with three classical β-turns and twisted β-hairpin without interstrand disulfide bonds. This is a novel peptide spatial structure that we propose to name boundless β-hairpin.
ID:864 - (2013). Polypeptide Modulators of TRPV1 Produce Analgesia without Hyperthermia. Mar Drugs 11 (12), 5100–15 [+]Transient receptor potential vanilloid 1 receptors (TRPV1) play a significant physiological role. The study of novel TRPV1 agonists and antagonists is essential. Here, we report on the characterization of polypeptide antagonists of TRPV1 based on in vitro and in vivo experiments. We evaluated the ability of APHC1 and APHC3 to inhibit TRPV1 using the whole-cell patch clamp approach and single cell Ca2+ imaging. In vivo tests were performed to assess the biological effects of APHC1 and APHC3 on temperature sensation, inflammation and core body temperature. In the electrophysiological study, both polypeptides partially blocked the capsaicin-induced response of TRPV1, but only APHC3 inhibited acid-induced (pH 5.5) activation of the receptor. APHC1 and APHC3 showed significant antinociceptive and analgesic activity in vivo at reasonable doses (0.01-0.1 mg/kg) and did not cause hyperthermia. Intravenous administration of these polypeptides prolonged hot-plate latency, blocked capsaicin- and formalin-induced behavior, reversed CFA-induced hyperalgesia and produced hypothermia. Notably, APHC3's ability to inhibit the low pH-induced activation of TRPV1 resulted in a reduced behavioural response in the acetic acid-induced writhing test, whereas APHC1 was much less effective. The polypeptides APHC1 and APHC3 could be referred to as a new class of TRPV1 modulators that produce a significant analgesic effect without hyperthermia. ID:994
- (2012). Lignan from thyme possessing inhibitory effect on ASIC3 current. J. Biol. Chem. , [+]
Novel compound was identified in acidic extract of Thymus armeniacus collected in the Lake Sevan region of Armenia. This compound, named sevanol, to our knowledge is the first low molecular weight natural molecule that has a reversible inhibition effect both on transient and sustained current of human ASIC3 channels expressed in Xenopus laevis oocytes. Sevanol completely blocked the transient component (IC50 353+/-23 μM) and partially (~45%) inhibited the amplitude of sustained component (IC50 of 234+/-53 μM). Other types of ASICs channels were intact to sevanol application except ASIC1a that showed more than 6 times less affinity to it as compared with inhibitory action on ASIC3 channel. To elucidate sevanol structure the set of NMR spectra in two solvents: d6-DMSO and D2O was collected and the complete chemical structure was confirmed by LC-ESI+-MS fragmentation. This compound is a new lignan built up of epiphyllic acid and two isocytril esters in positions 9, 10. In vivo administration of sevanol (1-10 mg/kg) significantly reversed of thermal hyperalgesia induced by complete Freund adjuvant (CFA) injection and reduced response to acid in writhing test. Thus we assume the probable considerable role of sevanol in known analgesic and anti-inflammatory properties of thyme.
ID:725 - (2012). Molecules to selectively target receptors for treatment of pain and neurogenic inflammation. Recent Pat Inflamm Allergy Drug Discov 6 (1), 35–45 [+]
Receptors that are involved in generation and transduction of pain signals attract much interest from the scientific and corporate communities. Good commercial prospects for successful development of effective analgesic drugs stimulate significantly the research. This article provides a brief overview of the key molecular targets, i.e. cell receptors, inhibition of which can lead to analgesia. Today transient receptor potential (TRP), purinergic (P2X) receptors and acidsensing ion channels (ASIC) are considered to be the most important proteins for perception of pain stimuli. These ionotropic receptors also participate in the development of inflammation; their hyperactivity leads to many pathological conditions and is closely associated with acute and inflammatory pain. Development of molecules capable to selectively modulate these receptors, their in vitro and in vivo effects, as well as perspectives for practical application described in patents and research articles are reviewed in this paper.
ID:679 - (2011). Spider venom peptides for gene therapy of Chlamydia infection. Antimicrobial agents and chemotherapy 55 (11), 5367–9 [+]
Spider venoms are vast natural pharmacopoeias selected by evolution. The venom of the ant spider Lachesana tarabaevi contains a wide variety of antimicrobial peptides. We tested six of them (latarcins 1, 2a, 3a, 4b, 5, and cytoinsectotoxin 1a) for their ability to suppress Chlamydia trachomatis infection. HEK293 cells were transfected with plasmid vectors harboring the genes of the selected peptides. Controlled expression of the transgenes led to a significant decrease of C. trachomatis viability inside the infected cells.
ID:545 - (2011). Novel lynx spider toxin shares common molecular architecture with defense peptides from frog skin. FEBS J. 278 (22), 4382–93 [+]
A unique 30-residue cationic peptide oxyopinin 4a (Oxt 4a) was identified in the venom of the lynx spider Oxyopes takobius (Oxyopidae). Oxt 4a contains a single N-terminally located disulfide bond, Cys4-Cys10, and is structurally different from any spider toxin studied so far. According to NMR findings, the peptide is disordered in water, but assumes a peculiar torpedo-like structure in detergent micelles. It features a C-terminal amphipathic α-helical segment (body; residues 12-25) and an N-terminal disulfide-stabilized loop (head; residues 1-11), and has an unusually high density of positive charge in the head region. Synthetic Oxt 4a was produced and shown to possess strong and broad-spectrum cytolytic and antimicrobial activity. cDNA cloning showed that the peptide is synthesized in the form of a conventional prepropeptide with an acidic prosequence. Unlike other arachnid toxins, Oxt 4a exhibits striking similarity with defense peptides from the skin of ranid frogs that contain the so-called Rana-box motif (a C-terminal disulfide-enclosed loop). Parallelism or convergence is apparent on several levels: the structure, function and biosynthesis of a lynx spider toxin are mirrored by those of Rana-box peptides from frogs. DATABASE: The protein sequence of oxyopinin 4a (Oxt 4a) has been submitted to the UniProt Knowledgebase (UniProtKB) under the accession number P86350. The coordinates and chemical shifts of Oxt 4a in complex with dodecylphosphocholine micelles have been deposited in the Protein Data Bank and Biological Magnetic Resonance Bank under the accession codes 2L3I and 17194, respectively. The nucleotide sequence encoding Oxt 4a has been submitted to the EMBL Nucleotide Sequence Database under the accession number FN997582.
ID:546 - (2011). The mining of toxin-like polypeptides from EST database by single residue distribution analysis. BMC Genomics 12, 88 [+]
Novel high throughput sequencing technologies require permanent development of bioinformatics data processing methods. Among them, rapid and reliable identification of encoded proteins plays a pivotal role. To search for particular protein families, the amino acid sequence motifs suitable for selective screening of nucleotide sequence databases may be used. In this work, we suggest a novel method for simplified representation of protein amino acid sequences named Single Residue Distribution Analysis, which is applicable both for homology search and database screening.
ID:690 - (2010). Cyanogen bromide cleavage of proteins in salt and buffer solutions. Anal. Biochem. 407 (1), 144–6 [+]
Protocols for recombinant polypeptide production should provide high yields and be efficient, user friendly, and time saving. To perform cyanogen bromide (CNBr) cleavage of fusion proteins, the majority of researchers first desalted and vacuum-dried samples and then dissolved them in aqueous formic or trifluoroacetic acid. We propose to exclude the desalting step and run CNBr cleavage directly. We show that the commonly used Tris-HCl, sodium phosphate, NaCl, imidazole, and guanidine-HCl do not interfere with the reaction under acidic conditions. Omitting the desalting step does not decrease the final yields of target products, as demonstrated for fusion proteins of different origin and composition.
ID:395 - (2010). Purification and characterization of biologically active peptides from spider venoms. Methods Mol. Biol. 615, 87–100 [+]
Spider venoms represent invaluable sources of biologically active compounds suitable for use in life science research and also having a significant potential for biotechnology and therapeutic applications. The methods reported herewith are based on our long experience of spider venom fractionation and peptides purification. We routinely screen new peptides for antimicrobial and insecticidal activities and our detailed protocols are also reported here. So far these have been tested on species of Central Asian and European spiders from the families Agelenidae, Eresidae, Gnaphosidae, Lycosidae, Miturgidae, Oxyopidae, Philodromidae, Pisauridae, Segestriidae, Theridiidae, Thomisidae, and Zodariidae. The reported protocols should be easily adaptable for use with other arthropod species.
ID:390 - (2009). Molecular diversity of spider venom. Biochemistry Mosc. 74 (13), 1505–34 [+]
Spider venom, a factor that has played a decisive role in the evolution of one of the most successful groups of living organisms, is reviewed. Unique molecular diversity of venom components including substances of variable structure (from simple low molecular weight compounds to large multidomain proteins) with different functions is considered. Special attention is given to the structure, properties, and biosynthesis of toxins of polypeptide nature.
ID:391 - (2009). Analgesic effect of a polypeptide inhibitor of the TRPV1 receptor in noxious heat pain models. Dokl. Biochem. Biophys. 424, 46–8 ID:635
- (2009). [New polypeptide components from the Heteractis crispa sea anemone with analgesic activity]. Bioorg. Khim. 35 (6), 789–98 [+]
Two new polypeptide components which exhibited an analgesic effect in experiments on mice were isolated from the Heteractis crispa sea tropical anemone by the combination of chromatographic methods. The APHC2 and APHC3 new polypeptides consisted of 56 amino acid residues and contained six cysteine residues. Their complete amino acid sequence was determined by the methods of Edman sequencing, mass spectrometry, and peptide mapping. An analysis of the primary structure of the new peptides allowed for their attribution to a large group of trypsin inhibitors of the Kunitz type. An interesting biological function of the new polypeptides was their analgesic effect on mammals, which is possibly realized via the modulation of the activity of the TRPV1 receptor and was not associated with the residual inhibiting activity towards trypsin and chymotrypsin. The analgesic activity of the APHC3 polypeptide was measured on the hot plate model of acute pain and was significantly higher than that, of APHC2. Methods of preparation of the recombinant analogues were created for both polypeptides.
ID:637 - (2008). Analgesic compound from sea anemone Heteractis crispa is the first polypeptide inhibitor of vanilloid receptor 1 (TRPV1). J. Biol. Chem. 283 (35), 23914–21 [+]
Первый ингибитор термочувствительных рецепторов TRPV1, активно принимающих участие в механизмах воспаления и передачи болевых ощущений, был выделен из экстракта нематоцистов морской анемоны Heteractis crispa. В экспериментах in vivo на мышах рекомбинантный аналог природного полипептида, названного АРНС1, проявил значимую анальгетическую активность, сопоставимую с действием опиоидов. В отличие от опиоидов, действие АРНС1 не приводит к наркотическому эффекту; поэтому обнаруженный полипептид имеет огромное практическое значение для разработки новых обезболивающих и противовоспалительных средств.
ID:87 - (2008). Bacterial production of latarcin 2a, a potent antimicrobial peptide from spider venom. Protein Expr. Purif. 60 (1), 89–95 [+]
Natural venoms are promising sources of candidate therapeutics including antibiotics. A recently described potent antimicrobial peptide latarcin 2a (Ltc 2a) from Lachesana tarabaevi spider venom shows a broad-spectrum antibacterial activity. This peptide consists of 26 amino acid residues and therefore its production using chemical synthesis, although trivial, is costly. We describe an easy approach to Ltc 2a production in Escherichia coli using the conventional fusion partner thioredoxin. Latarcin 2a synthetic gene was cloned into the expression vector pET-32b, which was then used to transform E. coli BL21(DE3) strain. His-tagged fusion purification was achieved using metal-chelate affinity chromatography. Since no methionine residues are present in the latarcin 2a sequence, cyanogen bromide could be effectively utilized to separate the target product from the carrier protein. Reverse-phase HPLC was used as the final step of purification; the final yield was approximately 3 mg/L of bacterial culture. To increase the yields, we attempted incorporation of Ltc 2a tandem repeats into the fusion protein; however, production rates greatly decreased due to enhanced fusion toxicity. Moreover, we probed constructs to produce an Ltc 2a dimer and the Ltc 2a propeptide to study their functional properties. Recombinant peptides were produced at appreciable yields and biological tests to determine their activities were performed. Latarcin 2a is the first linear peptide from spider venom and one of the first membrane-active peptides from venomous animals to be biosynthetically produced.
ID:387 - (2008). Cyto-insectotoxins, a novel class of cytolytic and insecticidal peptides from spider venom. Biochem. J. 411 (3), 687–96 [+]
Eight linear cationic peptides with cytolytic and insecticidal activity, designated cyto-insectotoxins (CITs), were identified in Lachesana tarabaevi spider venom. The peptides showed antibiotic activity towards Gram-positive and Gram-negative bacteria at micromolar concentrations as well as toxicity to insects. The primary structures of the toxins were established by direct Edman sequencing in combination with enzymatic and chemical polypeptide degradation and MS. CITs represent a novel class of cytolytic molecules and spider venom toxins. They are the first example of molecules showing equally potent antimicrobial and insecticidal effects. Analysis of L. tarabaevi venom gland expressed sequence tag database revealed the primary structures of the protein precursors; eight peptides homologous with the purified toxins were additionally predicted. CIT precursors share a conventional prepropeptide structure with an acidic prosequence and a processing motif common to most spider toxin precursors. The most abundant peptide, CIT 1a, was chemically synthesized, and its lytic activity on different bacterial strains, human erythrocytes and lymphocytes, insect cells, planar lipid bilayers and lipid vesicles was characterized. The spider L. tarabaevi is suggested to have evolved to rely on a unique set of linear cytolytic toxins, as opposed to the more common disulfide-containing spider neurotoxins.
ID:386 - (2006). Latarcins, antimicrobial and cytolytic peptides from the venom of the spider Lachesana tarabaevi (Zodariidae) that exemplify biomolecular diversity. J. Biol. Chem. 281 (30), 20983–92 [+]
Семейство коротких линейных полипептидных молекул — латарцинов — было найдено в яде паука Lachesana tarabaevi, часть из них была получена химическим синтезом и исследована на антибактериальное действие. Бактерицидная активность латарцинов соответствовала лучшим антимикробным пептидам, обнаруженным у различных видов животных. Большой терапевтический потенциал этих простых по структуре полипептидных молекул будет реализован, с большой долей вероятности, в самое ближайшее время.
ID:86 - (2005). A novel strategy for the identification of toxinlike structures in spider venom. Proteins 59 (1), 131–40 [+]
We compared two different approaches to sequence information analysis from the expressed sequence tag (EST) library constructed for the venom glands of the spider Agelena orientalis. Some results were more illustrative and reliable by the contig analysis technique, whereas our novel method, with specific structural markers introduced for protein structure detection, allowed us to overcome some limitations of the contig analysis. A novel technique was suggested for the identification in data banks of the spider's ion channel inhibitor toxins using primary structure features common to all spiders. Analysis of about 150 polypeptides made it possible to introduce 3 primary structure motifs for spider toxins: the Principal Structural Motif (PSM), which postulates the existence of 6 amino acid residues between the first and second cysteine residue and the Cys-Cys sequence at a distance of 5-10 amino acid residues from the second cysteine; the Extra Structural Motif (ESM), which postulates the existence of a pair of CXC fragments in the C-region; and the Processing Quadruplet Motif (PQM), which specifies the Arg residue at position -1 and Glu residues at positions -2, -3, and/or -4 in the precursor sequences just before the postprocessing site. In the processed data bank we found 48 toxinlike structures with ion channel inhibitor motifs. These include agelenin earlier isolated from Agelena opulenta and 25 more homologous sequences, 15 homologs of mu-agatoxin 2 from the spider Agelenopsis aperta, 3 structures with low homology to omega-agatoxin-IIIA, and 4 new structures. Also we showed that toxinlike structures exceed two thirds of the overall database sequences.
ID:194 - (2001). An ERG channel inhibitor from the scorpion Buthus eupeus. J. Biol. Chem. 276 (13), 9868–76 [+]
Первый селективный блокатор K+ каналов ERG-типа BeKm, выделенный из яда скорпиона Buthus eupeus, был экспрессирован в гетерологичной системе и его биологические свойства, а также свойства нескольких мутантных аналогов, были изучены
ID:85на M-токах культуры клетокNG108-15. Анализ активности мутантных форм позволили установить наиболее значимые аминокислотные остатки в структуре токсина, а сам токсин стал первым опубликованным селективным ингибитором hERG каналов, который в настоящий момент продается на рынке биологических препаратов.