Study of complexation of single-stranded poly(rA) and poly(rU) with methylene blue.

To reveal the effect of DNA- or RNA-specific low-molecular compounds on cellular processes on the molecular level, we have carried out the studies with the application of spectroscopic methods. It is necessary for the understanding of structural-functional properties of nucleic acids in cell. In this work the interaction of DNA-specific thiazine dye methylene blue (MB) with synthetic polynucleotides poly(rA) and poly(rU) was studied.

Study of interaction of methylene blue with DNA and albumin.

The interaction of thiazine dye methylene blue (MB) with Calf thymus DNA and human blood serum albumin (HSA) has been studied. MB was revealed to stabilize the native structure of DNA and HSA, since the melting temperature of the complexes is shifted to higher values in relation to that of both macromolecules in pure state. It was also revealed that the absorption and fluorescence spectra of the MB-DNA complexes change significantly, while those of MB-albumin complexes do not change noticeably.

Study of complexes of Hoechst 33258 with poly(rA)-poly(rU) depending on various ionic strengths in the water-saline solution.

Comparative study of the complexes of groove-binding ligand Hoechst 33258 (H33258) with synthetic homopolynucleotides poly(rA)-poly(rU) and poly(dA)-poly(dT) has been carried out at various concentration ratios of r = ligand/nucleic acids (NA) and different ionic strengths of the water-saline solution 0.02, 0.04 and 0.

Spectroscopic study of interaction of various GC-content DNA with Hoechst 33258 depending on Na concentration.

Communicated by Ramaswamy H. Sarma.

Study of the influence of the ionic strength on complex-formation of ethidium bromide with poly(rA)-poly(rU).

Communicated by Ramaswamy H. Sarma.