[Mechanism of the formation of DNA-protein cross-links during the gamma irradiation of chromatin in aqueous solutions]. / O mekhanizme obrazovaniia sshivok "DNK-belok" pri gamma-obluchenii khromatina v vodnykh rastvorakh.

The method of gel electrophoresis was used to study DNA-protein cross-link formation in fragmentized chromatin gamma-irradiated in water solutions (0.03%). By introducing changes into irradiation conditions (for instance, the use of different gases saturating the solution and the administration of radical acceptors) and by the subsequent electrophoretic analysis (treatment of the exposed chromatin by dissociating mixtures and enzymes) the authors showed a covalent nature of the cross-links in a radiation-induced DNA-protein complex and found the value of G (a cross-link) to be 0.02.

[Molecular mechanisms of the radiation destruction and formation of cross links in chromatin in aqueous solutions]. / O molekuliarnykh mekhanizmakh radiatsionnoi destruktsii i obrazovaniia sshivok v khromatine v vodnykh rastvorakh.

The modified gel-electrophoresis techniques were used to study DNA destruction in oligonucleosomes of the chromatin and the formation of DNA-protein cross-links under the effect of 60Co-gamma-rays. The yields of DNA destruction were evaluated in different conditions of chromatin irradiation: they were comparable with the yields of single-strand breaks. The bonds in the DNA-protein polymer formed were found to be covalent. It was shown that the processes of formation of cross-links and peroxide radicals (hydroperoxides) were mutually exclusive.

[Radiation destruction of DNA and histone in the composition of the chromatin]. / Radiatsionnaia destruktsiia DNK i gistona v sostave khromatina.

A study was made of the radiolysis of low-molecular-weight chromatin in water solution (0.037%) at 273 K in the absence of O2. It was demonstrated by the gel-electrophoresis method that both fragments of the complex are destructed and polymers formed involving DNA and protein. In other words, "DNA-protein" cross-links are formed. The yield of these processes essentially decreases if the chromatin solution is irradiated in the presence of inositol (0.05 M), an OH radical acceptor. The formation of cross-links is connected with the recombination of macroradicals in DNA and histone or with the reaction of their conversion products with the functional groups of the chromatin fragments.