title: [Interaction of divalent metal ions with four-stranded polyriboinosinic acid].
abstract: Interaction of Mg2+, Ca2+, Cu2+ ions with the four-stranded poly(I) was studied using differential UV and visible spectroscopies. It was shown that, up to concentrations of approximately 0.1 M, Mg2+ and Ca2+ ions do not bind to heteroatoms of hypoxanthine of the four-stranded poly(I). Cu2+ ions interact with N7 (and/or N1) and O6 (through the water molecule of the hydrate shell of the ion). The latter seems to induce the enolization of hypoxanthine the deprotonation of N1, and, as a result, the transition of the four-stranded helix to single-stranded coils. Single-stranded chains form compact particles with an effective radius of about 100 A.
authors.affiliation: Verkin Physicotechnical Institute of Low-Temperature, National Academy of Sciences of Ukraine, Kharkov, Ukraine.
authors.forename: V A
authors.initials: VA
authors.lastname: Sorokin
authors.forename: V A
authors.initials: VA
authors.lastname: Valeev
authors.forename: G O
authors.initials: GO
authors.lastname: Gladchenko
authors.forename: M V
authors.initials: MV
authors.lastname: Degtiar
authors.forename: Iu P
authors.initials: IuP
authors.lastname: Blagoĭ
mesh_terms: D002413:Cations, Divalent; D008670:Metals / Q000737:chemistry*; D015394:Molecular Structure; D011069:Poly I / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods
chemical_list: D002413:Cations, Divalent; D008670:Metals; D011069:Poly I