Biopolymers and cell. 1994. Volume 10. № 2. 57 - 60

V. A. Sorokin, V. A. Valeev, G. 0. Gladchenko, Yu. P. Blagoi, O. A. Ryazanova, L. F. Sukhodub

ETHONIUM INTERACTION WITH SINGLE-CHAIN HOMOPOLYNUCLEOTIDES

Summary

    The interaction of single-chain homopolynucleotides and individual ribo- and desoxyribo-nucleotides with the effective antimicrobic preparation ethonium belonging to the group of nonintercalating substances is studied by the method of differential UV spectroscopy. Under conditions close to the physiological ones (pH 6, 0,1 M Na + ), ethonium does not bind to heteroatoms of individual nucleotides. However, in polymers ethonium is found to interact strongly with N(7) and N(l) of poly(A), N(3) of poly(C) and O(4) of poly (U). The affinity of ethonium for three atoms is much higher than for the oxygens of the phosphate groups of polymers. Its nucleotide selectivity of binding corresponds to the row: poly (A)^poly (U) >poly(C). Ethonium cannot substitute protons at N(3) of poly(U) and O(2) of poly(C) ribose, neither it interacts with O(2) of this poly-nucleotide.