[Study of the mechanism of the unwinding effect of destabilized helix of bacteriophage f1 gene 5 protein with the aid of model tripeptides].

Complexes of synthetic double-stranded polynucleotides and DNA with model peptides--L-Lys-L-Tyr-L-Lys and L-Lys-Gly-L-Lys have been investigated, using UV-spectroscopy. Polynucleotide complexes containing L-Lys-Gly-L-Lys were studied in order to consider the influence of lysyl residues on the polynucleotide melting temperature. It was shown, that L-Lys-L-Tyr-L-Lys lowers the melting temperature of all the polynucleotides studied, except poly(rI) . poly(C). The dependence of melting temperature of polynucleotide (DNA) . L-Lys-L-Tyr-L-Lys complexes upon the polynucleotide double helix form and GC-content has been detected. These effects have reflected the intercalation of peptide tyrosyl residues into one of the chains of the double-stranded polynucleotide. Correlation o the melting temperature dependences of polynucleotide complexes with gene 5 protein and L-Lys-L-Tyr-L-Lys upon polynucleotide double helix form and GC-content was found.