[DNA与二价金属离子的相互作用]

[Interaction of DNA with divalent metal ions].

作者信息

Kornilova S V, Sorokin V A, Blagoĭ Iu P, Valeev V A, Arutiunian S G

出版信息

Mol Biol (Mosk). 1991 May-Jun;25(3):648-57.

PMID:1944252

Abstract

The interaction between the native DNA macromolecules and Ca2+, Mn2+, Cu2+ ions in solutions of low ionic strength (10(-3) M Na+) is studied using the methods of differential UV spectroscopy and CD spectroscopy. It is shown that the transition metal ions Mn2+ exercise binding to the nitrogen bases of DNA at concentrations approximately 5 x 10(-6) M and form chelates with guanine of N7-Me(2+)-O6 type. Only at high concentrations in solution (5 x 10(-3) M) do Ca2+ ions interact with the nitrogen bases of native DNA. In the process of binding to Ca2+ and Mn2+ the DNA conformation experiences some changes under which the secondary structure of the biopolymer is within the B-form family. The DNA transition to the new conformation is revealed by its binding to Cu2+ ions.

摘要

采用差示紫外光谱法和圆二色光谱法，研究了低离子强度（10⁻³ M Na⁺）溶液中天然DNA大分子与Ca²⁺、Mn²⁺、Cu²⁺离子之间的相互作用。结果表明，过渡金属离子Mn²⁺在浓度约为5×10⁻⁶ M时与DNA的氮碱基结合，并与N7-Me(2⁺)-O6型鸟嘌呤形成螯合物。只有在溶液中高浓度（5×10⁻³ M）时，Ca²⁺离子才会与天然DNA的氮碱基相互作用。在与Ca²⁺和Mn²⁺结合的过程中，DNA构象发生了一些变化，在此过程中生物聚合物的二级结构属于B型家族。DNA与Cu²⁺离子的结合揭示了其向新构象的转变。