Publications by authors named "M O Bezhitadze"

By the method of optical activity it has been studied the temperature dependence of the triple helical refolding process of partially denatured collagen from the skin and swim bladder of the mirror carp, and also that of the rat skin. It is shown that reducing the renaturation temperature the triple helical refolding rate increases and is in perfect agreement with the earlier observed fact [1,2]. The temperature coefficient of the reaction rate in the investigated region of temperatures remains constant, this fact ought to point to the zero value of activity energy of cis-trans isomerization process since renaturation goes on without nucleation stage.

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A study has been done of the effect of neutral salts (NaCl and CaCl2) on the mechanism of type I collagen triple helix folding and unfolding in concentrated acetic acid solutions (2-8.8 M). It is shown that in these conditions, thermoabsorption and secondary structure change in heated solutions proceed in two consecutive stages.

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Activation parameters of fibril formation of evolutionary differing collagens were investigated. It has been shown that in a heated solution formation of collagen fibrils of different origin proceeds in different temperature regions related with the environmental temperature of species range. Enthalpy and free energy of the activation of fibril formation were measured.

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Difference in the mechanism of denaturation of collagen in the presence and absence of the terminal non-helical regions is shown.

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It is shown that in 0,5 M NaCl 8 M CH3COOH heat absorption and the second structure alteration in a heated solution proceed between two stages following one another, and besides, salts not only decrease the macromolecule denaturation temperature in total, but produce different destabilization effect on different regions. The presence of the thermostable domain in the macromolecule helical part permits investigation of the folding mechanism of the triple collagen helix under partial denaturation. The localization and biological role of the stable domain in the triple helix formation are suggested.

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