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The analysis of conformationally stable (conformational conservative) tetrapeptides selected from protein structures deposited in PDBSelect data bank has been fulfilled. The subset contained 943 tetrapeptide amino acid sequences and there were merely five 3D protein segment representatives for each sequence. As a result, the conclusion has been drawn on the basis of DSSP annotation analysis that in the majority of cases (900 of 943) alpha-helical conformation is obvious. Different than alpha-helix, in particular, the left-handed polyproline II helical conformation was observed in 43 sequences. The physical and chemical properties of conformationally stable peptides taken from the appropriate sample were estimated by the average hydrophobicity/hydrophilicity of tetrapeptides. The results of calculations show that the "neutrality" towards hydrophobicity/hydrophilicity is representative of conformationally stable oligopeptides. It should be noted, that dispersion of hydrophobicity/hydrophilicity distribution is sufficiently lower than for the test subsets. Thus, the conformationally stable oligopeptides present a distinct group of local protein structures which are very close with respect to conformational and physicochemical properties. In accordance with our developed theory of specific long range interactions these peptides are the objects being quite useful for effective mutual molecular recognition.

Conservative regions varying in length from 30 to 70 nucleotides (nt) are revealed as a result of interspecies comparison of homologous nucleotide sequences of the loci, genes controlling early development in Drosophila species. These regions are observed at the intermediate level between transcription factor binding sites (usually about 7-10 nt) and the nucleosome repeat unit (165-210 nt). Segments found are located mainly in the area of known functional elements of the locus (cis-regulatory modules: enhancers, a proximal promoter, a coding segment). Conservative domains occupy less than a half of the full enhancer length and contain practically all annotated transcription factor binding sites. A quasi periodical pattern of conservative region disposition is in accord with the experimental nucleosome localization pattern. The distance between neighboring domains is about 84 nt, i.e. a pitch of nucleosome DNA super helix. A repeatable accuracy of the distance permits of treating the delineated conservative regions as co-phased blocks and stating that these domains are close in the space being located at neighboring coils of the nucleosome DNA super helix.

The work presents the results of an exhaustive conformational analysis of β-turns involving amino acid residues with disallowed backbone conformation of the polypeptide chain. It is known that the first residue of the β-turn (Asn47) of the distal β-hairpin in the α-spectrin SH3-domain is characterized by sterically disallowed main chain conformation (values of the dihedral angles (φ and ψ are in the right bottom quadrant of the Ramachandran plot). All α-spectrin structures with the anomalous elements deposited in the PDB were analysed. We hypothesized that the formation of disallowed conformation may occur through the fixation (due to the SH3 domain structure) of the adjacent to the β-turn amino acid residues with the β-structure. These residues are disposed in such a manner that β-turn conformation of the residues contributes just to the disallowed local conformation of this residue whereas any other β-turn conformations (with allowed local conformation) are impossible. To test this hypothesis an exhaustive conformational analysis of the β-bend has been performed by altering internal coordinates (two pairs of φ and ψ angles and two Ω angles). The conformations were selected as a result of grid search procedure with. 1 degrees step that corresponded to stereochemically allowed local deformations of the polypeptide chain segment forming the β-turn. In all conformations obtained the local conformation of Asn47 rests in the disallowed region. The conformations found include conformations coinciding with experimentally determined structures from the PDB as well as an additional variant that differs from X-ray structure in values of a pair of φ and ψ angles of the second residue belonging to the β-bend. Values of these angles fall in the region of the Ramachandran plot near the line φ = 0 (and negative values of ψ) i.e. in strongly disallowed region without experimental points. Therefore the additional variants of the β-turn local deformation are impossible to observe in experiment. Thus, the idea that disallowed conformation is intruded to the β-bend by fixation of adjacent residues receives confirmation in this work. The topological limitations in a context of the structure in such kind of β-hairpins exclude the allowed local conformations.

We propose a method for magnetic sorting of cell suspensions able to differentiate not only cells with single specific antigen on their surface, but also cells with a group of pre-defined antigens. Individually, each antigen of this group may be present on surfaces of non-selected cells. However, only the simultaneous presence of all given antigens on the cell surface means that such a cell should be separated. The method is of interest, for purification of cell suspensions from malignant cells, in particular, for purification of bone marrow material for autologous transplantation in leukemia.

The classification of amino acid residues based on the events of contact formation between distinct amino acid and selected nucleotides was constructed. Thus, the most integral properties, that characterize interactions in organization of DNA-protein complexes, were used. We applied the Voronoi-Delaunay tessellation to draw statistics of contacts and area of contacts for the set included 1937 DNA-protein complexes. Similarities of amino acid residues have been searched for based on the comparison of corresponded rows and matrixes of contacts and areas of contacts. Nine measures of distance were used for estimation of rows similarity degree. The procedure of clustering amino acids in groups included three hierarchical and two nonhierarchical methods. A total tree was built using nine techniques of estimating distance with three hierarchical clustering methods. It was shown that clustering centers in the main groups are always constant while other relationships between objects vary. Clustering of binary associations was found for the most amino acids. Major classes of up to six amino acids correspond to the certain local structures of the polypeptide chain in the context of amino acid composition. These data should be taken into account when designing DNA-protein ligands.

In the work the arguments are presented in favor of the idea on the role of conformationally stable oligo-peptides in specific long-distance interactions in phenomena of molecular recognition during various biological processes. Original authors' and literature data are taken into account. The examples of conformationally stable short oligopeptides participation in alpha-helix and collagen type structures formation are given simultaneously with theoretical approaches. The conformationally stable oligopeptides obtained in the course of PDB bank analysis are discussed. The role of amino acids sequence in collagen helix formation is shown.

The correlation was observed between DNA segments characterized by periodic patterns of nucleotides and nucleosome DNA binding sites predicted by the profiles of local DNA flexibility. Exons of human type I and VII collagen genes loci have been chosen as a sample set of periodic DNA segments. It was pointed that short periodic exons coding fibrillar part of these proteins are localized near borders of the DNA sequence that binds the histone core. One of the borders of exon and of this sequence coincide as a rule. In non-fibrillar parts of collagen genes exons (longer on average) dispose, in contrast, in any place of the DNA sequence bound to the nucleosome core.

It was shown that selective interactions between helical segments of macromolecules can realize in globular proteins in the segments characterized by the same periodicities of charge distribution i.e. between conformationally conservative oligopeptides. It was found that in the macromolecules of alpha-helical proteins conformationally conservative oligopeptides are disposed at a distance being characteristic of direct interactions. For representatives of many structural families of alpha-type proteins specific disposition of conformationally conservative segments is observed. This disposition is inherent to a particular structural family. Disposition of conformationally conservative segments is not related to homology of the amino acid sequence but reflects peculiarities of native 3D-architectures of protein globules.

On the basis of the theory of specific long-range interaction between long molecules the approach has been elaborated for the "fast reading" of nucleotide sequences in sole DNA molecule. Firstly, a stretching force applies to the molecule that causes its unwinding from B-form to so called S-form. Then, a molecule disposes in a stretched state on the background. After this, the electrostatic potential is estimated in the space along the DNA filament. Information obtained is sufficient for the deduction of the nucleotide sequence in DNA. Another approach to the "reading" of information reduces to the measurement of the filament element deformation induced by electrostatic field from the electrode that stretches the filament by alternating current applied.

The process of globular structure formation from a long molecular chain has been examined. In the course of this process, various regions of the chain interact with one another. We classify the bonds formed during this process as "correct" and "erroneous" ones. The term "correct" bonds implies the bonds characteristic for a completely formed native globular structure. All other bonds can be treated as "erroneous". It was demonstrated that the process of globule formation may proceed actually without the formation and the following decay of "erroneous" bonds. Our model permits one to avoid the examination of numerous "erroneous" variants since, between the regions of the chain that form "correct" bonds, long-distance interactions characterized simultaneously by high selectivity take place. The existence of interactions of this kind facilitates the drawing together and subsequent interaction of just these regions of the chain that yield "correct" bonds. Based on the data bank analysis, it was demonstrated that the model elaborated is valid not only for abstract structures but also for real polypeptide chains capable of forming protein globules and superhelical fibrils.

Fourier spectra of nucleotide sequences from chromosome 15 of Gallus gallus have been obtained. The periodical structures of several Ig locus fragments have been characterized. The uniqueness of Fourier spectra of the locus of the Ig light chain and its fragments (such as a variable region, a constant region, an enhancer, and several other fragments) among Fourier spectra of other fragments of chromosome 15 is demonstrated.

The distribution of secondary structures along the polypeptide chains of spider proteins spidroins 1 and 2 and their recombinant analogs has been studied by statistical methods. It was found that these proteins in the monomolecular form contain only trace amounts of beta-structures. At the same time, the regions of the sequence including Ala and Gly are predicted as helical-containing (with alpha-helices and left-helices of polyproline II type). An analysis of literature data and our data obtained in this study shows that the main conformation of the polypeptide chain solutions of spidroins 1 and 2 and their recombinant analogs in water solutions is the left-helix of polyproline II type with some contaminations of alpha-helices and a very small share of beta-structures. The transition to the state with extended conformations, which are peculiar to mature filaments of spider webs, requires the dehydration of the polypeptide chain backbone. Thus, the genesis of beta-structure in spider web proteins is determined by the conditions of conformation transitions between the main regular conformations of the polypeptide chain backbone.

The influence of imino acids on the thermodynamic characteristics of collagen type structures in various collagens has been analyzed. It was shown that the basic mechanism of entropy increase in the protein-water system consists in the alteration in the number of cooperative segments accompanying the increase in imino acids content, which can be observed during the melting of the fibrous macromolecule. The range of variation in the physical characteristics of cooperative units is determined, in particular, by the variability of hydrogen bond parameters. This is displayed in a broadening of the bands of NH-valence vibrations and the half-widths of transitions in post-denatured structures. Thus, the basic mechanism of the influence of imino acids on thermodynamic characteristics of collagens is related to the complex nature of the melting process. The dehydration-hydration mechanisms of native and denatured states become significantly different upon replacement of any amino acid by an imino acid.

A new method for the rigorous analysis of DNA-protein contacts has been developed on the basis of Voronoi tessellation. This method permits one to determine close neighbors on the atomic level and compute the area of contact by edges of Voronoi polyhedra. Based on the results of the study of 1109 protein-DNA complexes from PDB, it was demonstrated that about one third of the contacts are the contacts with positively charged Arg and Lys. There is distinct amino acid prevalence for nucleotides: for A - Pro; for T - His; for G - Asp; for C - Trp, Asp, Glu. Therefore, GC pairs prefer to interact with negatively charged residues, and alanine and methionine, whereas AT pairs prefer to interact with histidine and unpolar residues.

Regions with a quasiperiodical location of exon--intron sites have been found in the loci of genes of I and VII type collagens (with a total length of exons more than 15% of the entire size of the locus). The periods observed are similar to periods typical for the nucleosomal level of the organization of chromatin. It was shown that the sites consisting of successively arranged exons and introns form groups involving two to five such regions of the same length. The groups encoding the fibrillar regions of the gene product contain more than 50% of exons. The regions are on the average 165 nt long, which is close to the minimal nucleosomal repeat length observed in some regions of the eukaryotic genome. In the nonfibrillar region of the gene of VII type collagen, groups of several exon-intron pairs with an average length of 227 nt were identified. The change in the length of exon-introns sites on going from the nonfibrillar to the fibrillar moiety occurs in a jump, which is clearly seen on a periodogram of the locus.

Promoters recognized by deltaA-RNA and deltaH-RNA polymerase have different periodic patterns their nucleotide disposition. By using the special method of Fourier analysis for symbolic sequences. Fourier spectra of the primary structure of promoters transcribed bv deltaA-RNA and deltaH-RNA polymerase were obtained. For two data sets, a small one and a big one, a stepwise discriminant analysis with jackknife test based on the spectral characteristics of each of the promoters was performed. It was shown that it is possible to classify the data with the accuracy of 100% sets into classes: promoters that are recognized by the deltaA-RNA polymerise and promoters that are recognized by the deltaH-RNA polymerase. Significant correlations between the promoter strength and the characteristics of their Fourier spectra were obtained. Thus, the periodicity in nucleotide distribution along the polynucleotide chain is the attribute sufficient for promoter recognition by RNA polymerase holoenzyme.

A new method for determining bound water was developed, which is based on precise measurements of the enthalpy of water evaporation from a sample using differential scanning calorimetry.

The formation of beta-turns in globular proteins has been studied by the method of molecular mechanics. Statistical method of discriminant analysis was applied to calculate energy components and sequences of oligopeptide segments, and after this prediction of I type beta-turns has been drawn. The accuracy of true positive prediction is 65%. Components of conformational energy considerably affecting beta-turn formation were delineated. There are torsional energy, energy of hydrogen bonds, and van der Waals energy.

Step-by-step computations of octapeptide structures was performed for human collagens I and III. It was shown that computational results (coordinates of atoms) practically coincide with X-ray data for the collagen fragment.

Sequences of spidroin 1 and 2 from spiders belonging to various species were analyzed by Fourier analysis. Specific periodical patterns were found in various segments of the sequences. These characteristic periodicities vary within the same proteins as well as between spidroin 1 and spidroin 2 sequences. It is possible that alterations in periodicity help to recognize contact sites between the molecules. Spidroins of 2 type have similar sequence structure consisting of four parts with a particular periodical pattern. These parts are a constant C-terminal part, a long-periodical part, a short-periodical part, and a constant N-terminal part.

The quantitative characteristics of a spectral portrait of the nucleotide sequence of E. coli oriC were determined by the method of matrix Fourier analysis.

The regions of initiation of replication of some bacterial genomes were studied by the method of Fourier matrix analysis. A generalized spectral portrait of the primary structures of E. coli-like regions of initiation of replication in bacteria was obtained, which reflects the features of their structural and functional organization. It contains well-pronounced peaks that correspond to the periods T = 2, 11, 17, 27, 86-105 of nucleotides. The peaks corresponding to T = 9, 13, 14, 18, 19, 33-35, 45-47, 74-85, 106-110 are less pronounced. The uniqueness of the Fourier spectrum corresponding to the region of initiation of replication of E. coli oriC was considered by the example of the complete genome of E. coli. Some regions of the E. coli genome were identified that differ from oriC in the primary structure but have Fourier spectra resembling the spectrum of oriC. A number of these regions are alternative points of initiation of replication in sdrA(rnh) mutants of E. coli, the others are localized in yet unidentified regions of the E. coli genome but are capable, in our opinion, to participate in the initiation of replication. Thus, from the similarity of spectral portraits of different regions of the genome, it was possible to reveal several regions that have similar functions, i.e., are involved in initiation of replication.

The statistical analysis of hydrogen bonds distribution in space structures of globular proteins has been done. The parameters of H-bonds in the different secondary structures of globular proteins were collected. In alpha-helices besides the canonical 1-5 H-bonds (the mean length 3 A), 1-4 H-bonds were observed (the mean length 3.2 A). The histograms of length and angular distributions of the bonds are presented. It was found on the basis of quantum chemistry calculations that most H-bonds in alpha-helices are double or bifurcated.

It was proposed to elucidate the mechanism of unique biological biocompatibility of carbon materials used for making endoprostheses for medicinal practice. For this purpose, a method of comparing the geometry of individual globular and fibrillar proteins and carbon structures (fullerenes) was advanced, and a comparative analysis of the spatial structure of fullerene C60 and the amino acid sequences of 286 proteins was made. Based on a high degree of similarity in the positions of atoms of the polypeptide chains of proteins and peptides and the corresponding atoms of fullerene and of other structural parameters revealed by the comparison of the spatial structures using mathematical simulation, the phenomenon of biological compatibility was interpreted as an "insertion" of fullerenes into the structure of protein molecules in place of structurally similar amino acid sequences, i.e., as a "prosthetics" at the molecular level. It is proposed that fullerenes can "simulate" structurally similar short peptides in biological processes. It was shown that noncarbon biogenic atoms play a large role in the formation of specific structure of protein molecules.

Along with symmetrical features (palindromes, direct and inverted repeats), periodicities in the disposition of nucleotides in the origin of chromosome replication oriC from E. coli were studied by means of Fourier analysis. Peaks corresponding to the periods T = 2, 17, 95-100 nucleotides are the highest in the Fourier spectrum of oriC. Peaks corresponding to the periods T = 3, 11, 19, 13, 24, 27, 28, 41, 79-81 nucleotides are also prominent, but not so high. Thus, the main periodicities of the oriC spectrum of are not multiple of the B-DNA sugar-phosphate backbone period, which destabilize DNA at oriC and contributes to the spontaneous unwinding of DNA. The differences between the Fourier spectrum of oriC and those of regions adjacent to oriC are demonstrated.

Periodicities in the position of E.coli RNA polymerase promoter contacts on several promoters (lacUV5, T7 A3, tetR, lambda cin, lambda c17, RNA1, and trp S.t.) were found by means of Fourier analysis. The comparison of the Fourier spectrum of core RNA polymerase contacts on the lacUV5 promoter and that of holoenzyme revealed a more prominent 7-periodicity in the Fourier spectrum of holoenzyme contacts. 6-, 7-, and 8-periodicities were found in the primary structure of the majority of E.coli promoters. It is shown that RNA polymerase recognizes specific periodic patterns in the promoter structure.

The problem in the calculation of Van der Waals interactions in protein globules based on the theory of condensed media was considered. The Van der Waals interactions are represented as energies of interaction of regions with a uniform density distribution. A definition of the local dielectric constant as a function of coefficients of absorption of molecular groups with a particular conformation was introduced. The applicability of this approach was estimated. The theory enables one to circumvent the problems arising in calculations based on pairwise additive approximation. The methods provides a high accuracy in determining the local features of spatial structures of globular proteins and physicochemical characteristics of their constituent amino acids and molecular groups.

The hydrogen bond distributions in 123 protein structures with the atom coordinates established at a resolution of less than 2 A were analyzed. The peculiarities of hydrogen bond distributions with respect to the lengths and remoteness of contacting residues in the primary structure were established. A hierarchy of H-bond energy distribution in the spatial structure of protein globules was demonstrated. The role of hydrogen bonds in the formation of domain structure and their special properties in proteins with different types of secondary structure are discussed.

We have justified a Van der Waals approach for the problem of domains structure in globular proteins. A method for isolation of hierarchy of Van der Waals interactions in the space of protein globule has been found out. The definition of hierarchy's levels in the spatial structure of macromolecules is effected by the position of maxima in the distribution of potential energy of interactions. Multilevels system for domain structure organization of globular proteins and method for isolation of domains on different levels of energetical hierarchy has been established. Using this method we have revealed regions of different stability in 15 proteins globule.

Fourier spectra of E. coli promoter DNA sequences have been obtained. The periodical structure of individual promoter sequences is characterized. E. coli promoter sequences are classified according to their Fourier spectra using three feature sets: 1--the number of peaks in Fourier spectra; 2--values of power spectra for promoter primary structures and their similarity with physical periodicities in the backbone of polynucleotide; 3--the presence of blocks made of equal nucleotides. The comparison of Fourier spectra of promoter sequences and corresponding genes is provided. The conclusion that different ways of stabilization of promoter secondary structure in the case of different primary structure periodicities is drawn. The intermittence of AT- and GC-blocks, and variety of Fourier spectra mean DNA hydrate shell in DNA promoters is non-contiguous and non-stable at junction points. Characteristic features of prokaryotic promoters Fourier spectra differ from human promoters.

We have identified the lac repressor amino acids which form cross-links with partially depurinated DNA and hence are proximate to it. Only lysine-33 is cross-linkable in specific complex with lac operator. At the presence of inducer molecules lysine-33 remains cross-linkable. However, the N-terminal alpha-aminogroup was additionally cross-linked with the boundaries of lac operator. We conclude that orientation of the DNA-binding domain of the repressor is reversed by inducer binding.

The effect of ethanol and medium pH on thermodynamic parameters and cooperativity of pepsinogen thermal denaturation have been studied by scanning microcalorimetry. Addition of 20% (v/v) ethanol decreases the protein temperature of denaturation by 10.7 degrees C at pH 6.4 and by 15.8 degrees C at pH 8.0. It decreases the denaturation heat capacity change of pepsinogen from 5.8 to 4.2 kcal/K.mol, but has no effect on the number of energetic domains (regions melting in an "all-or-none" manner). The dependences of calorimetric denaturation enthalpy on denaturation temperature in both aqueous solution and 20% ethanol are linear and converge at about 95 degrees C, which coincides with the converge temperature of similar dependencies shown for a number of proteins in aqueous and water-alcohol solutions. A change of pH from 5.9 to 8.2 in 20% ethanol has been shown to cause a decrease of the number of cooperatively melting regions in pepsinogen. This process involves no changes either in the secondary structure or in the local surroundings of aromatic amino acids. It is concluded that ethanol addition has no effect on pepsinogen denaturation cooperativity until there is sufficient influence on intramolecular charge distribution, taking place upon a change of pH.

The thermal stability of phenylalanyl-tRNA-synthetase (PTS) from E. coli and T.thermophilus HB 8 was studied in solution at various conditions by scanning microcalorimetry. It has been shown that the value of heating rate, concentration of the enzyme and Mg2+ ions in the solution affects the parameters of thermal denaturation of both enzymes. The higher thermal stability of PTS from T. thermophilus was observed as well as the independence of its properties upon broad variations of experimental conditions. The role of thermostability of the enzymes are discussed with respect to the biological properties of E. coli and T.thermophilus.

On the basis of X-ray determined coordinates specified with computer graphics and new data on amino acids sequence in the structure of Bacillus intermedius 7P ribonuclease there were analysed potentially charged residues and found ionic pairs binding independently denaturing regions-energetic domains. Five clusters of charged amino acids were found in the protein structure and several ionic bonds between the energetic domains were discovered: Asp7, Asp11-Arg109 and Lys26-Asp53,Glu72. Breaking of the latter makes their heat denaturation independent. Local surrounding of the ionic bonds is characterized and their role in the structure and cooperative properties of the globule is discussed.

Circular dichroism technique has been used for investigating the conformation of histone H1 and H5 C-terminal fragments and beta-endorphin. It has been shown that in aqueous solution these polypeptides adopt preferably the left-handed helical conformation of the poly-L-proline II type. The linear temperature dependence of the CD value during solution heating was found to be broken in the temperature interval between 50 and 55 degrees C. It was supposed to occur due to the conformation destruction.

The paper exhibits results of hydration shell Monte Carlo calculations in poly-L-proline II and extended helix conformation and in alpha-helical and beta-structural conformations for comparison. It was found that left-handed helix of poly-L-proline II type as well as epsilon-helix are characterized by very favorable hydration. Therefore this conformation has preference as compared to other standard conformations of the main polypeptide chain. This determined inevitability of cold denaturation of protein.

The dependence of denaturation transition thermodynamic parameters in various collagens from imino acid compositions has been analysed. Computational and experimental data suggest independence of the collagen molecule hydration on imino acid composition and sequence in the polypeptide chain. The continuous net of hydrogen bonds is interrupted, if imino acid residues occur in the sequence of amino acid residues, as follows from Monte Carlo computations, because the hydrogen of NH-group plays sufficient role in water shell formation for this conformation. As a consequence, entropy of denatured collagen-water system increases hand by hand with increasing imino acid content and therefore delta S increases. The increase of enthalpy of transition from imino acid content is determined by favorable Van der Waals interactions of pyrrolidine rings in native triple helical collagen structure. It was pointed out that proline role is determined by decreasing hydration in the single stranded polypeptide chain in Polyproline II conformation that leads to an increase of entropy of the polypeptide-water system. Thus, the collagen structure formation by imino acids is promoted in the water media due to single chain left-helical conformation being unfavorable for proline residues as well as due to the enthalpy nature of the triple helix stabilization.

It has been shown by the method of conformational analysis that conformation of the polypeptide chain of a collagen molecule varies from one type of sequence to another, but in all the sequences the only two types of conformations can be characterized by minimal conformational energy. The collagen molecule as a whole is a combination of the single-bond Rich and Crick model and new double-bonded structure. Rigorous comparison with "thick" conformations obtained by Scheraga and coworkers was undertaken using precise calculations with flexible proline.

Local conformational states of fibrous fragments of myosin molecules from striated muscle have been studied. Analysis of the amino acid sequences of the rat embryonic skeletal muscle myosin heavy chain and the nematode myosin heavy chain have been performed with the aim to estimate the influence of electrostatic interactions on secondary structure stability of these fragments. The heterogeneity of stability of alpha-helical conformation along the fibrous fragment have been found on the basis of estimation of interaction between side group charges and between side group charges and main chain charges. Periodically located short sections have been found in the N-terminal half of the myosin rod where clusters of Asp and Glu destabilize alpha-helical structure being ionized. Changes of the distribution of charges near the latter sections bring about conformational transitions from left-handed polyproline II helix to right alpha-helix or vice versa. The new scheme of orientation of fibrous part of the cross-bridge in relation to the thick filament for various stages of muscle contraction process suggests asynchronous character of transitions in the different sites. It may be proposed that existence of alteration left- and right-helical fragments in N-terminal half of fibrous part of heavy myosin chain determines zigzag form of this part of myosin molecule in resting muscle. A model of the cross-bridge movement in the course of ATP hydrolysis has been suggested.

Ethanol and pH influence on the number and dimensions of cooperative regions in pepsin molecule was studied by scanning microcalorimetry. It is shown that ethanol solution causes a decrease of temperature of protein denaturation but does not influence the number of energetic domains. While changing pH from 6.7 to 2.0 the number of thermodynamic cooperative units (defined as the ratio delta Hcal/delta Heff) decreases from four to two. This process, as shown by CD technique, is followed by changes neither in the secondary structure, nor in the local environment of aromatic amino acids. A conclusion is made that the distinctions in cooperative characteristics of the protein globule at different pH are determined by electrostatic interactions of separate parts of the molecule.

By the method of SHF-dielectrometry there was studied hydration of collagens isolated from different frog tissues of related species. Hydration was shown to be tissue-specific, i.e. the quantity of hydrate water in collagen 1 isolated from different animals being constant.