Tritium planigraphy: from the accessible surface to the spatial structure of a protein.

The method of tritium planigraphy, which provides comprehensive information on the accessible surface of macromolecules, allows an attempt at reconstructing the three-dimensional structure of a protein from the experimental data on residue accessibility for labeling. The semiempirical algorithm proposed for globular proteins involves (i) predicting theoretically the secondary structure elements (SSEs), (ii) experimentally determining the residue-accessibility profile by bombarding the whole protein with a beam of hot tritium atoms, (iii) generating the residue-accessibility profiles for isolated SSEs by computer simulation, (iv) locating the contacts between SSEs by collating the experimental and simulated accessibility profiles, and (v) assembling the SSEs into a compact model via these contact regions in accordance with certain rules. For sperm whale myoglobin, carp and pike parvalbumins, the lambda cro repressor, and hen egg lysozyme, this algorithm yields the most realistic models when SSEs are assembled sequentially from the amino to the carboxyl end of the protein chain.

[Comparison of dynamic properties of various globular proteins and polyglutamic acid in alpha-helical and coil states. Rayleigh scattering of Mossbauer radiation data].

Classical model system: Poly-L-glutamic acid (Poly-Glu) was investigated in a disordered coil state (at pH-7.0) and in helix state (at pH 2.0) by Rayleigh scattering of Moessbauer radiation technique.

[Study of the dynamics of human serum albumin by coherent Rayleigh dispersion of Mossbauer radiation].

The measurements of angle dependencies of total and elastic Rayleigh scattering of Mossbauer radiation intensities have been performed for human serum albumin (HSA) with hydration degrees h = 0.13 and h = 0.4.

Mössbauer spectroscopy of oxygenated haemoglobins.

Murine tetrameric oxyhaemoglobin and insect monomeric erythrocruorin were studied. A doublet with the Lorentz form of lines (delta EQ = 2.22 mm s-1; delta alpha-Fe = 0.

[Study of protein dynamics using Mössbauer spectroscopy].

Last experimental results of the study of protein dynamics by Mössbauer absorption spectroscopy and Rayleigh scattering of Mössbauer radiation are reviewed. Dynamical properties of proteins following from the theoretical treatment of these data are described.

[Study of the effect of hydration on the dynamics of various globular proteins by Rayleigh scattering of Mössbauer radiation].

Hydration relationships of the elastic scattering fraction of Mössbauer radiation were studied for human serum albumin (HSA), pancreatic trypsin inhibitor and lysozyme within hydration degrees 0 less than or equal to h less than or equal to 0.75 g/g (at T = 295 degrees K) and temperatures 100K less than or equal to T less than or equal to 320 K (for HSA only at h = 0.03; 0.

[Role of conformational sub-states on the reaction capacity of protein molecules].

A review of the recent data on protein dynamics (mainly myoglobin) by X-ray technique, Mössbauer spectroscopy and Rayleigh scattering of Mössbauer radiation is given. The connection between dynamical and functional properties of biological systems are discussed.

[Mössbauer spectroscopy of intramolecular mobility in chromatophores from Rhodopseudomonas spheroides].

Mobility of the Mössbauer label attached to the membrane proteins and the Mössbauer probe embedded into the lipid matrix of the bacterial chromatophores were studied. Positive correlation was established between the dynamic properties of hydrophobic compartments in the chromatophores and functional electron--transport activity at the level of quinone cofactors associated with the photosynthetic reaction centres.

[Study of the three-dimensional structure of proteins by means of tritium labeling. II. Intramolecular distribution of tritium in the N-terminal part of myoglobin and the tertiary structure of protein].

The possible use of the method of 3H-label introduction by means of a 3H-atom beam for investigating the three-dimensional structure (surface) of proteins was studied. The intramolecular distribution of tritium in the N-terminal part of 3H-labelled sperm-whale myoglobin was studied. The results obtained are in good agreement with the X-ray analysis data on the polypeptide chain of the protein molecule.

[Study of three-dimensional structure of proteins by means of tritium labeling. I. Free amino acids as a model of residues in an unfolded polypeptide chain].

Probabilities of the incorporation of tritium label into various amino acids with alanine as a standard have been determined by "bombing" solid targets with a 3H-atom beam (2 000 K). The results show that amino acids can be used with sufficient accuracy as models of amino acid residues in a polypeptide chain under 100%, accessibility. The resulting coefficients, if taken into consideration in the analysis of intramolecular distribution of tritium in short tryptic peptides of TMV protein, will yield an equiprobable distribution in the case when the label has been introduced into a peptide.

[The mechanism of binding of sodium dodecyl sulfate by lysozyme].

It has been shown that the mechanism of complex formation changes at variation of the detergent concentration. At low concentrations the complex is stabilized, mainly, by hydrophobic interactions. The boded molecules are immobilized inside the globules.

[Debye-Waller factor of Rayleigh scattering of Mössbauer radiation at substances with strong conformation motions].

A model was developed to describe conformational motion of macromolecules. A new formula was derived for the Debye-Waller factor in accordance with this model. The model proposes the existence of fluidlike motions of fragments within the volume of some A3.

[Study of chromophore dynamics by means of Rayleigh scattering of Mossbauer radiation].

The temperature dependence of rayleigh scattering of Mössbauer radiation was studied for two samples of the chromatophores with different relative humidity (P/Ps = 0.35 and 0.94).

[Free-radical label--new approach to the study of dynamics of lipid systems].

A new method of EPR-spectroscopy--the recombination of free radicals appearing as a result of indirect radiolysis of biological molecules after a low temperature irradiation--is applied to the study of molecular dynamics of phosphatidylcholine dimyristoyl in mass and in the structure of liposomes above and below the transition temperature. It was shown, that the mobility of lipid molecules in crystalline liposomes is higher than in the structure of liquid-crystalline liposomes. The addition of cholesterol in liposome membranes decreases the lateral molecular motion of lipids in crystalline and liquid-crystalline state, in the latter case the effect of cholesterol addition is more pronounced.

Free radical label: new approach to the study of super-slow molecular dynamics of lipid systems.

A new method of EPR-spectroscopy, the recombination of free radicals appearing as a result of indirect radiolysis of biological molecules after a low temperature irradiation, was applied to the study of molecular dynamics of dimyristoyl phosphatidylcholine in mass and in the structure of liposomes above and below the transition temperature. It was shown that the mobility of lipid molecules in crystalline liposomes was lower than in the structure of liquid-crystalline liposomes. The addition of cholesterol in liposome membranes decreased the lateral molecular motion of lipids in crystalline and liquid-crystalline states; in the latter case, the effect of cholesterol addition was more pronounced.

Incorporation of hydrophilic protein modified with hydrophobic agent into liposome membrane.

The hydrophilic protein-enzyme, alpha-chymotrypsin, can be bound to the liposomal membrane after the preliminary increase in hydrophobicity induced by acylation of protein amino groups with palmitic chloroanhydride. The efficacy of binding depends on the degree of modification. The bound enzyme almost completely preserves its catalytic properties and the ability to interact with a high molecular weight inhibitor.

[Study of the dynamics of water-protein systems by the technic of gamma-resonance spectroscopy].

The possibility of using gamma resonance spectroscopy (GRS) for studying the dynamics of water-protein systems is shown in the present work. The experiments were carried out on an albumin-water system. The results obtained are compared with those obtained by the spin label method under the same conditions.