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Interaction of divalent metal ions with poly(riboinosinic acid)
Author(s) -
Sorokin Victor A.,
Valeev Vladimir A.,
Degtyar Marina V.,
Gladchenko Galina O.,
Blagoi Yuri P.
Publication year - 2000
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20001101)201:17<2408::aid-macp2408>3.0.co;2-p
Subject(s) - chemistry , deprotonation , crystallography , cooperativity , ion , divalent , metal ions in aqueous solution , molecule , inorganic chemistry , organic chemistry , biochemistry
Methods of differential UV and visible spectroscopy are used to study the interaction of Mg 2+ , Ca 2+ , Mn 2+ and Cu 2+ ions with four (4×I)‐ and single‐stranded poly I in solutions with 1 mol·l –1 Na + . Up to concentrations of about 0.1 mol·l –1 Mt 2+ , Mg 2+ and Ca 2+ ions do not bind to heteroatoms of hypoxanthine of 4×I. Cu 2+ ions interact with N7 and/or N1 and possibly with O6 through the water molecule of the hydrate shell of the ion. It is likely that the interaction with O6 causes enolization of the hypoxanthine, N1 deprotonation and, as a result, this leads to the melting of the four‐stranded helix. In single‐stranded chains, Cu 2+ ions induce the formation of compact particles which have the effective radii r e ≈ 100 Å. The Mn 2+ ‐induced differential spectra are similar to those observed in the presence of Cu 2+ ions but in the case of Mn 2+ they occur at concentrations about two orders of magnitude higher. In contrast to the positive cooperativity of the Cu 2+ binding to bases of single‐stranded poly I, their interaction with 4×I has the negative cooperativity.