[DNA与Cu2+离子相互作用过程中螺旋-线圈转变的量热研究]

[Calorimetric study of the helix-coil transition in DNA during interaction with Cu2+ ions].

作者信息

Kornilova S V, Yasem P, Grigor'ev D N, Kapinos L E, Totova Ia, Blagoĭ Iu P, Galkin V L

机构信息

Verkin Physicotechnical Institute of Low Temperatures, National Academy of Sciences of Ukraine, Khar'kov, Ukraine.

出版信息

Biofizika. 1998 Jan-Feb;43(1):46-52.

PMID:9567176

Abstract

Using the method of differential scanning calorimetry, the DNA helix-coil transition was studied in solutions (10(-3) M Na+, 10(-3) M tris HCl, pH 7.0) containing divalent copper ions at relative metal ion concentrations (Mt2+/PDNA) ranging from 0.2 to 20. Dependences of the melting temperature and enthalpy on relative ion concentration were determined. An aggregation of Cu(2+) + DNA complexes in the range of average ion concentration was established. It is shown that the melting enthalpy of "units" increases with copper ion concentration. The data obtained were compared with values determined by UV-spectroscopy. Association constants for Cu2+ binding to DNA were defined by the ligand theory.

摘要

采用差示扫描量热法，在相对金属离子浓度（Mt2+/PDNA）范围为0.2至20的含有二价铜离子的溶液（10(-3) M Na+，10(-3) M 三羟甲基氨基甲烷盐酸盐，pH 7.0）中研究了DNA的螺旋-线圈转变。测定了熔解温度和焓对相对离子浓度的依赖性。确定了在平均离子浓度范围内Cu(2+) + DNA复合物的聚集情况。结果表明，“单元”的熔解焓随铜离子浓度增加。将所得数据与通过紫外光谱法测定的值进行了比较。通过配体理论定义了Cu2+与DNA结合的缔合常数。