title: [Interaction of gene 5 protein of phage f1 with single and double-stranded DNA and polynucleotides].
abstract: The fluorescence method was used to reveal some differences in the interaction of gene 5 protein of phage f1 with single- and double-stranded polynucleotides (DNA). The binding with the duplexes is non-cooperative and the Kapp is twice lower than that for the cooperative formation of the complex with single-stranded structures. In the complex with a double-stranded polynucleotide (DNA) the protein cover 3 nucleotide pairs. The complex dissociates with a lower concentration of salt and the contribution of the energy of nonelectrostatic interactions to the total energy of complex formation for it is lower than for the complex with single-stranded DNA. In the complex of protein with single-stranded structure the fluorescence of the tyrosine (Tyr) residues is quenched to a greater degree and their accessibility to the external quencher is lower than that of the complex with double-stranded polynucleotides (DNA). The suggestion is made that in destabilization of nucleic double helices by gene 5 protein of phage f1, a great role belongs to Tyr residues because of their high affinity to single-stranded structures and because of their different localization in the complexes with single- and double-stranded polynucleotides.
mesh_terms: D003090:Coliphages / Q000032:analysis*; D004247:DNA; D004277:DNA, Single-Stranded; D004355:Drug Stability; D005814:Genes, Viral; D007700:Kinetics; D008433:Mathematics; D011089:Polydeoxyribonucleotides; D011485:Protein Binding; D013329:Structure-Activity Relationship
chemical_list: D004277:DNA, Single-Stranded; D011089:Polydeoxyribonucleotides; D004247:DNA
vernacular_title: Vzaimodeĭstvie belka gena 5 faga f1 s odno- i dvukhspiral'nymi DNK i polinukleotidami.