[Determination of depth of immersion of chlorophyll P680, pheophytin, and a secondary electron donor in the subchloroplast preparations of photosystem II from pea].

The immersion depths (r) of the main functional components of the reaction centres of the Photosystem 2 in the thylakoid membranes were determined by ESR at 77K. It was shown that P680(+), Pheo(-) (pheophytin), and Z(+) (secondary electron donor) the r value was 2-4, 4-7 and 14-20 A, respectively. On the basis of these and reference data a model of location of the Photosystem 2 reaction centre components in the photosynthetic membrane was suggested.

[Effect of hydration on the molecular dynamic properties of human serum albumin at low temperatures].

The effect of temperature and hydration on phosphorescence of chromatophores and on saturation curves of ESR spectra of spin labels covalently bound to human serum albumin was studied. It has been shown that at 90-260 degrees K albumin hydration results in intensification of motions of hydrophobic parts with low frequencies (vc less than or equal to 10(3) s-1) and does not affect the motions of hydrophobic and surfacial parts with high frequency.

[Mobility of free radicals connected with serum albumins at 30-230 K].

This paper presents experimental results of inner dynamics study of human serum albumin by a series of physical methods: a) the method of radical pairs recombination based on measuring of recombination rate of radical pairs included to surface layers of a protein globule; b) the method of spin labels with saturation transfer technique. The complex of methods used in this work permits to measure the mobility of physical labels and environment matrix in a wide correlation frequency range 10(-4)-5.10(10) s-1 in 30-230 K temperature range.

[Magnetic interaction of manganese with pheophytin anion-radical and chlorophyll cation-radical in reaction centers of the photosystem II].

The influence of Mn on saturation curves of ESR spectra of Ph(-) and P(+)(680) at 1-200K in samples with different content of Mn has been studied. An analysis of these data and those on photoinduced changes of fluorescence yield of chlorophyll leads to the conclusion that the Mn-containing centre in Photosystem 2 is a cluster of 4 Mn atoms, two of which can be replaced by Mg(2+) or any other divalent metal. The distances between Mn Na Ph as well as between Mn and P(680) have been estimated.