Publications by authors named "Khromova T"

The terahertz frequency absorption spectraof DNA molecules reflect low-frequencyinternal helical vibrations involvingrigidly bound subgroups that are connectedby the weakest bonds, including thehydrogen bonds of the DNA base pairs,and/or non-bonded interactions. Althoughnumerous difficulties make the directidentification of terahertz phonon modes inbiological materials very challenging, ourresearch has shown that such measurementsare both possible and fruitful. Spectra ofdifferent DNA samples reveal a large numberof modes and a reasonable level ofsequence-specific uniqueness.

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The conformational transition collagen-like triple helix in equilibrium with chains of oligotripeptides Z-(Gly-Pro-Pro)n-OMe with n = 6, 7, 8 in water by variation of solution temperature and sample concentration has been studied using IR-, CD-spectroscopy and microcalorimetry methods. The straight line correlation between the obtained value of the transition enthalpy and entropy and the number of the triplets (3n - 2), involved in the interpeptide set of hydrogen bonds was revealed. Evidently the effect of terminal groups is really weak in this case, and the interpeptide bonds of the triple helix may be regarded as equivalent one another.

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The ir amide bands of the triple-helical polytripeptides and collagens upon hydration of films are investigated. On the basis of our assignment of the amide I components, the formation of hydrogen bonds between the peptide backbone and structural water is studied. The C1O1--HOH hydrogen bonds are found more ordered than the C3O3--HOH hydrogen bonds.

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By the IR-spectroscopy method successive stages of hydrate envelope formation of the collagen-like triple-helical structure of the monodisperse synthetic polytripeptide Z-(Gly-Pro-Pro)8-OMe were studied. The multistep-type process is followed by isomorphic transitions of the triple-helical structure and by the increasing of hydrogen bond strength.

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Infrared spectra were measured for both aqueous (D2O) solution and the solid state of form II poly-L-proline in the amide I region as a function of the temperature. The temperature range includes the region where a precipitation is known to occur. From the analysis of spectra of hydrated films and aqueous solutions at different temperatures one can see that there are some peptide C = O-groups which are bounded with water.

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