Biopolymers and cell. 2007; 23 (2): 122 - 129

Electrophoretic study of conformational transitions in poly(G) as a function of salt

M. I. Zarudnaya, A. V. Stepanyugin, A. L. Potyahaylo, D. M. Hovorun

Conformational transitions in poly(G) as a function of salt concentration has been studied first by the method of electrophoresis. It was shown that only one band of polymer is observed at concentration of monovalent cations > 10 mM. This band corresponds to the four-stranded form of poly(G). At lower salt concentration two overlapping bands are observed. The band with lower electrophoretic mobility corresponds to four-stranded form of polymer and the band with higher mobility corresponds to single-stranded form. Electronic absorption spectrums of several homopolyribonucleotides after their staining with toluidine blue in agarose gels have been presented. It was discovered that the shape of spectrum depends both on polymer and its form. The Dl_max of absorption spectrums of four-stranded and single-stranded forms of poly(G) is about 20 nM.