title: [A compact form of DNA in solution. III. Influence of the ion composition of the solution on the compactization process of double-stranded DNA in the presence of peg].
abstract: The data showing the features of the DNA compactization process in PEG-containing solutions of chlorides of different alkaline metals (LiCl, KCl, RbCl and CsCl) and an ammonium salt (CH3-(CH2)17-N-(CH3)3Br) are presented. The data indicate that the formation of a compact form of the double-stranded DNA in PEG-containing water-salt solutions depends not only on the PEG concentration and ionic strength but on tha cation nature as well. The compactization occurs most easily in the presence of Na+-ions. This indicates a specific character of interaction between Na+-ions and DNA phosphate groups which may be due to an optimum structural fit between the hydrated Na+-ions and orientation of the phosphate groups in the DNA molecule. The nature of forces involved in the processes of the intramolecular compactization and intermolecular aggregation of double-stranded DNA molecules in water-salt solution is discussed. The difference between the effect of Na+ and that of K+-ions on the compactization process at the ionic strengths close to physiological values makes it possible to suggest that the changes of the tertiary structure of double-stranded DNA which accompany its function in vivo may take place under conditions of a decreased water activity at the expense of relatively slight changes in ion composition of the water surrounding DNA.
mesh_terms: D001665:Binding Sites; D002414:Cations, Monovalent; D002942:Circular Dichroism; D004247:DNA; D009690:Nucleic Acid Conformation; D009994:Osmolar Concentration; D011092:Polyethylene Glycols; D000644:Quaternary Ammonium Compounds; D012995:Solubility
chemical_list: D002414:Cations, Monovalent; D000644:Quaternary Ammonium Compounds; D011092:Polyethylene Glycols; D004247:DNA
vernacular_title: Kompaktnaia forma DNK v rastvore III. Vliianie ionnogo sostava rastvora na protsess kompaktizatsii dvukhtsepochechnoĭ DNK v prisutstvii polietilenglikolia