[Dependence of the rate of EPR spin-lattice relaxation of certain proteins on temperatures in the interval 6-22 K]. / Zavisimost' skorosti spin-reshetochnoi relaksatsii EPR signalov nekotorykh belkov ot temperatury v intervale 6-22 K.

It was shown, that rate of spin-lattice relaxation EPR signals of ferredoxin in temperature interval 9-22 K is proportional to T5. The mechanism of spin-lattice relaxation of non crystalline systems that explains the experimentally observed strange peculiarities of temperature dependence of relaxation rate, for a number of globular proteins, has been considered.

[Heat capacity of native DNA fibers at 2-25 K]. / Teploemkost' nativnykh volokon DNK pri temperaturakh 2-25 K.

The data on low-temperature heat capacity (2-25 K) of native DNA strands at different humidities are presented, which take into account the specificity of hydration of DNA due to its chemical composition (GC-content). The temperature dependence of DNA heat capacity (Cp = f(T)) at 2-4 K was analyzed. Analysis of Cp = f(T) involves both the ordinary Debay density and excessive low-energy density of oscillatory states (DOS) peculiar to noncrystalline solids. It is concluded that heat capacity of DNA at very energies (less than 1 K) is well described in terms of the generally accepted model of two-level systems. The nature of excessive DOS at energies 3-10 K is related to oscillatory excitations on structural inhomogeneities, which can represent clusters of hydrate water molecules (approximately 1-2 nm) "grown" in DNA matrix.

[Difference in DNA enthalpies in the helical and coiled states near 0 K]. / Raznost' éntal'pii DNK v spiral'nom i klubkoobraznom sostoianiiakh vblizi 0 K.

On the basis of experimental data of DNA heat capacity in a wide range of temperatures the fundamental characteristics of DNA-H(0)0-the enthalpy of helix coil transition at 0(0)K were estimated. H(0)0 = 8.41 +/- 1.6 kJ/MBP. It was shown that a deviation from Nernst theorem (resulting from metastability of the system) was not obtained within the range of experimental error.

[Heat capacity of DNA in native and denatured states]. / Teploemkost' DNK v nativnom i denaturirovannom sostoianiiakh.

Heat capacity of DNA in native and denatured states was estimated by the method of microcalorimetry. This value was shown to depend on the transition temperature and is determined by an increase of the number of oscillative freedom degrees of the polynucleotide chains in the state of statistical coils, and by hydrophobic effects and by "the melting of water ridge" located in native DNA in the B-form.