title: [Interaction of synthetic pentapeptide with DNA: specificity of binding and compactness of DNA].
abstract: Binding of synthetic pentapeptide Val-Thr-Thr-Val-Val-N2H2Dns (where Dns is a residue of 5-dimethylamino naphthyl-1-sulfonic acid) is studied by circular dichroism, electron microscopy and fluorescence methods. It is found that this peptide can self-associate in aqueous solution as revealed from the concentration-dependent changes in the UV absorbance and fluorescence spectra. At high peptide concentration (3.10(-4) M) massive peptide aggregates are formed in solution and can be visualized by electron microscopy. It is shown that pentapeptide binds to DNA predominantly in a self-associated form and exhibits preferences for certain nucleotide sequences. It binds more strongly to poly(dG).poly(dC) and poly[d(A-C)].poly[d(G-T)] than to poly(dA).poly(dT). The complex with poly(dA).poly(dT) dissociates in the presence of 0.05 M NaCl, whereas the complex with poly(dG).poly(dC) is stable even in the presence of 0.2 M NaCl. The binding is a cooperative process which is accompanied by compaction of DNA at peptide/DNA base pair ratios greater than 2. At the initial stage of the compaction process the coalescence of DNA segments covered by bound peptide molecules results in the formation of DNA loops stabilized by interaction between bound peptide molecules. Increasing peptide/DNA ratio leads to the formation of rod-like particles as revealed from electron microscopy studies. Further increase in the peptide concentration leads to folding of fibrillar macromolecular complexes into globula each containing a single DNA molecule.
authors.forename: N Iu
authors.initials: NIu
authors.lastname: Sidorova
authors.forename: T E
authors.initials: TE
authors.lastname: Semenov
authors.forename: A N
authors.initials: AN
authors.lastname: Surovaia
authors.forename: Iu Iu
authors.initials: IuIu
authors.lastname: Vengerov
authors.forename: S A
authors.initials: SA
authors.lastname: Strel'tsov
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D002942:Circular Dichroism; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004214:Distamycins / Q000378:metabolism; D005456:Fluorescent Dyes; D007700:Kinetics; D008854:Microscopy, Electron; D009842:Oligopeptides / Q000138:chemical synthesis / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D004268:DNA-Binding Proteins; D004214:Distamycins; D005456:Fluorescent Dyes; D009842:Oligopeptides; C030000:stallimycin; D004247:DNA
vernacular_title: Vzaimodeĭstvie sinteticheskogo pentapeptida s DNK: spetsifichnost' sviazyvaniia i kompaktizatsiia DNK.