Tselepi-Kalouli E, Katsaros N
Institute of Physical Chemistry, Demokritos National Research Center, Athens, Greece.
J Inorg Biochem. 1989 Dec;37(4):271-82. doi: 10.1016/0162-0134(89)85002-0.
The interaction of [Ru(NH3)5Cl]2+ and [Ru(NH3)6]3+ complex ions with calf thymus DNA has been studied at various r values (r = [Mn+]/[DNA-P]). Electronic spectra of metal-DNA solutions have been recorded and compared to the spectra of metal, as well as of DNA, solutions. Melting curves have been taken for the determination of DNA melting temperature (Tm) in the presence of the above complex ions. The results showed a biphasic melting of the DNA strands for relatively high r values. The Tm for the first phase increased with increasing r values, indicating metal ion interaction with the phosphate moieties of the DNA. The appearance of a second-phase melting, in connection with electronic spectra, pH values, and conductivity measurements of metal ion solutions, is indicative of the initial complexes' transformation to [Ru(NH3)5OH]2+, which binds preferentially to double-stranded rather than single-stranded DNA, thus leading to a second melting curve at a higher temperature than the first one.
已在不同的r值（r = [Mn⁺]/[DNA-P]）下研究了[Ru(NH₃)₅Cl]²⁺和[Ru(NH₃)₆]³⁺络合离子与小牛胸腺DNA的相互作用。记录了金属-DNA溶液的电子光谱，并与金属溶液以及DNA溶液的光谱进行了比较。已绘制了熔解曲线，以测定上述络合离子存在下DNA的熔解温度（Tm）。结果表明，在相对较高的r值下，DNA链呈现双相熔解。第一阶段的Tm随着r值的增加而升高，表明金属离子与DNA的磷酸基团发生了相互作用。结合电子光谱、pH值和金属离子溶液的电导率测量，第二阶段熔解的出现表明初始络合物转化为[Ru(NH₃)₅OH]²⁺，它优先与双链而非单链DNA结合，从而导致在比第一阶段更高的温度下出现第二条熔解曲线。
