Tamara A. Balashova

Ph.D. (Chemistry)

E-mail: taba@nmr.ru

Selected publications

  1. Nolde S.B., Vassilevski A.A., Rogozhin E.A., Barinov N.A., Balashova T.A., Samsonova O.V., Baranov Y.V., Feofanov A.V., Egorov T.A., Arseniev A.S., Grishin E.V. (2011). Disulfide-stabilized helical hairpin structure and activity of a novel antifungal peptide EcAMP1 from seeds of barnyard grass (Echinochloa crus-galli). J. Biol. Chem. 286 (28), 25145–53 [+]

    This study presents purification, activity characterization, and (1)H NMR study of the novel antifungal peptide EcAMP1 from kernels of barnyard grass Echinochloa crus-galli. The peptide adopts a disulfide-stabilized α-helical hairpin structure in aqueous solution and thus represents a novel fold among naturally occurring antimicrobial peptides. Micromolar concentrations of EcAMP1 were shown to inhibit growth of several fungal phytopathogens. Confocal microscopy revealed intensive EcAMP1 binding to the surface of fungal conidia followed by internalization and accumulation in the cytoplasm without disturbance of membrane integrity. Close spatial structure similarity between EcAMP1, the trypsin inhibitor VhTI from seeds of Veronica hederifolia, and some scorpion and cone snail toxins suggests natural elaboration of different functions on a common fold.

  2. Yampolsky I.V., Balashova T.A., Lukyanov K.A. (2009). Synthesis and spectral and chemical properties of the yellow fluorescent protein zFP538 chromophore. Biochemistry 48 (33), 8077–82 [+]

    Members of the green fluorescent protein (GFP) family become chromophoric through a unique pathway based on autocatalytic modifications of their amino acid residues. The yellow fluorescent protein zFP538 from the button polyp Zoanthus possesses unique spectral characteristics that are intermediate between those of the green and orange-red fluorescent proteins. In this study, we used chemical synthesis to resolve conflicting data from crystallographic and biochemical analyses of the zFP538 chromophore structure. We synthesized 2-(5-amino-1-oxopentyl)-5-(4-hydroxybenzylidene)-3-methyl-3,5-dihydro-4H-imidazol-4-one (5), which can spontaneously react intramolecularly to form cyclic imine (7). Compound 7 represents the native chromophore structure reported in the crystallographic study. We have also discovered an unusual isomerization of a 2-acylimidazolone to a 2,6-diketopiperazine derivative. The zFP538 chromophore is a complex system with intriguing chemical and spectral behavior, properties that have led to discrepancies in the interpretation of its structure. Our study supports the findings of previous crystallographic work, which postulated a cyclic imine chromophore structure within the native zFP538 protein, and also provides an explanation for experimental results obtained in the biochemical characterization of zFP538-derived chromopeptides.

  3. Pakhomov A.A., Pletneva N.V., Balashova T.A., Martynov V.I. (2006). Structure and reactivity of the chromophore of a GFP-like chromoprotein from Condylactis gigantea. Biochemistry 45 (23), 7256–64 [+]

    Here we present the study of the chromophore structure of the purple chromoprotein from Condylactis gigantea. Tandem mass spectrometry and 1H and 13C NMR of the chromopeptide reveal that the protein contains a chromophore with a chemical structure identical to that of the red fluorescent protein from Discosoma sp. A single A63G substitution demonstrates that the nature of the first amino acid of the XYG chromophore-forming sequence is dispensable for the chromoprotein red shift development. It has been recently proposed that post-translational reactions at the acylimine, a chemical group that accounts for the red fluorescence, might be an additional source of spectral diversity of proteins homologous to the Aequorea victoria green fluorescent protein (GFP). We have examined the reactivity of the chromophore acylimine group within the C. gigantea purple chromoprotein. Like other proteins with the acylimine-modified chromophore, the purple chromoprotein suffers a hypsochromic spectral shift to the GFP-like absorbance (386 nm) upon mild denaturation. NMR analysis of the chromopeptide suggests this hypsochromic spectral shift is due to H2O addition across the C=N bond of the acylimine. However, unlike the red fluorescent protein from Discosoma sp., denatured under harsh conditions, the wild-type chromoprotein exhibits only slight fragmentation, which is induced by complete hydrolysis of the acylimine. A model suggesting the influence of the amino acid X side chain on protein fragmentation is presented.

  4. Shenkarev Z.O., Paramonov A.S., Balashova T.A., Yakimenko Z.A., Baru M.B., Mustaeva L.G., Raap J., Ovchinnikova T.V., Arseniev A.S. (2004). High stability of the hinge region in the membrane-active peptide helix of zervamicin: paramagnetic relaxation enhancement studies. Biochem. Biophys. Res. Commun. 325 (3), 1099–105 [+]

    Zervamicin IIB is a 16 amino acid peptaibol that forms voltage dependent ion channels with multilevel conductance states in planar lipid bilayers and vesicular systems. Stability of the hinge region and intermolecular interactions were investigated in the N- and C-terminally spin-labelled peptide analogues. Intermolecular and intramolecular paramagnetic enhancement indicates that zervamicin behaves as a rigid helical rod in methanol solution. There are no high amplitude hinge-bending motions, and the peptaibol is monomeric up to concentration 1.5 mM. Stability of the hinge region illustrates the helix stabilising propensity of the Pro residue in membrane mimic environments and implies absence of significant conformational rearrangement due to voltage peptaibol activation.

  5. Pakhomov A.A., Martynova N.Y., Gurskaya N.G., Balashova T.A., Martynov V.I. (2004). Photoconversion of the chromophore of a fluorescent protein from Dendronephthya sp. Biochemistry Mosc. 69 (8), 901–8 [+]

    A green fluorescent protein from the coral Dendronephthya sp. (Dend FP) is characterized by an irreversible light-dependent conversion to a red-emitting form. The molecular basis of this phenomenon was studied in the present work. Upon UV-irradiation at 366 nm, the absorption maximum of the protein shifted from 494 nm (the green form) to 557 nm (the red form). Concurrently, in the fluorescence spectra the emission maximum shifted from 508 to 575 nm. The green form of native Dend FP was shown to be a dimer, and the oligomerization state of the protein did not change during its conversion to the red form. By contrast, UV-irradiation caused significant intramolecular changes. Unlike the green form, which migrates in SDS-polyacrylamide gels as a single band corresponding to a full-length 28-kD protein, the red form of Dend FP migrated as two fragments of 18- and 10-kD. To determine the chemical basis of these events, the denatured red form of Dend FP was subjected to proteolysis with trypsin. From the resulting hydrolyzate, a chromophore-containing peptide was isolated by HPLC. The structure of the chromophore from the Dend FP red form was established by methods of ESI, tandem mass spectrometry (ESI/MS/MS), and NMR-spectroscopy. The findings suggest that the light-dependent conversion of Dend FP is caused by generation of an additional double bond in the side chain of His65 and a resulting extension of the conjugated system of the green form chromophore. Thus, classified by the chromophore structure, Dend FP should be referred to the Kaede subfamily of GFP-like proteins.

  6. Ovchinnikov Y.A., Ivanov V.T., Evstratov A.V., Sumskaya L.V., Melnik E.I., Chumburidze T.S., Portnova S.L., Balashova T.A. (1973). Sandwich complexes as a functional form of the enniatin ionophores. FEBS Lett. 36 (1), 65–71 [+]

    The ability of the enniatin cyclodepsipeptides (CDP) (fig. 1) to form complexes with alkali metal ions (M+) and induce ionic permeability in artificial and biological membranes has been described in a number of papers [ 1,2]. The complexes were found to be equimolar in both solutions and in the crystalline state; by analogy with valinomycin and the nactins the role of the M+ carriers across the membrane was ascribed to them [3,49. In the present paper evidence is produced showing that an important part in the functioning of this group of ionophores is played by complexes with 2: 1 and 3:2 macrocycle:cation ratios.

  7. Bystrov V.F., Ivanov V.T., Portnova S.L., Balashova T.A., Ovchinnikov Yu.A. (1973). Refinement of the angular dependence of the peptide vicinal NH-CaH coupling constant. Tetrahedron 29 (6), 873–877 [+]

    The refined dependence of the peptide NHCαH vicinal coupling constant on the dihedral angle θ have been derived on the basis of the accumulated experimental data. The mean permissible values (in Hz) are approximated by 3JNHCH = 9·4 cos2 θ - 1·1 cos θ + 0·4 An analogous relationship for the sum of two vicinal NH-CαH2 coupling constants in the glycyl residue have been calculated from the above dependence. Measurements on N-methylacetamide in various solvents and in the presence of an alkali salt showed the vicinal constant NH-CH to vary by not more than ± 3%. Some of the other proposed 3JNHCH(θ) dependencies give too low values for the cis-oriented NH and CαH bonds. This may be due to the fact that in these correlations the data for compounds with cis-amide bonds have been used for 0° - θ - 90° region of the dependence.