Cusumano Matteo, Di Pietro Maria Letizia, Giannetto Antonino
Contribution from Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, University of Messina, Messina, Italy.
Inorg Chem. 1999 Apr 19;38(8):1754-1758. doi: 10.1021/ic9809759.
The interaction of the platinum(II) polypyridine complexes Pt(bipy)(2), Pt(quaterpy), Pt(terpy)(n-Rpy) and Pt(bipy)(py)(2) (bipy = 2,2'-bipyridine; terpy = 2,2':6',2' '-terpyridine; quaterpy = 2,2':6',2' ':6' ',2' "-quaterpyridine; n-R = H, 2-CH(3), or 4-CH(3) ) with double-helix DNA has been studied with a variety of experimental techniques. Induced circular dichroism, strong hypochromism and red shifts of the absorption maxima of the complexes, increase in melting temperature and viscosity of DNA, and inhibition of the reaction of the complexes with thiourea in the presence of DNA, characterize the processes. Intercalation, implying the whole molecule or part of it, is the suggested binding mode. The binding constants, K(B), determined spectrophotometrically at 25 degrees C, pH 7, and I = 0.15 M, using the McGhee-von Hippel approach, increase in the order Pt(bipy)(py)(2)< Pt(terpy)(py)< Pt(quaterpy), on increasing aromatic planar surface extension. The steric interference with double helix of the methyl group in Pt(terpy)(2-Mepy) destabilizes the interaction by reducing the stacking surface.
已使用多种实验技术研究了铂（II）多吡啶配合物Pt（bipy）(2)、Pt（quaterpy）、Pt（terpy）(n-Rpy)和Pt（bipy）(py)(2)（bipy = 2,2'-联吡啶；terpy = 2,2':6',2''-三联吡啶；quaterpy = 2,2':6',2' ':6' ',2''-四联吡啶；n-R = H、2-CH(3)或4-CH(3)）与双螺旋DNA的相互作用。配合物的诱导圆二色性、强烈的减色效应和吸收最大值的红移、DNA熔点和粘度的增加以及在DNA存在下配合物与硫脲反应的抑制作用，是这些过程的特征。所建议的结合模式是插入，这意味着整个分子或其部分。使用McGhee-von Hippel方法在25℃、pH 7和I = 0.15 M条件下通过分光光度法测定的结合常数K(B)，随着芳香平面表面延伸的增加，按Pt（bipy）(py)(2)< Pt（terpy）(py)< Pt（quaterpy）的顺序增加。Pt（terpy）(2-Mepy)中甲基对双螺旋的空间干扰通过减少堆积表面使相互作用不稳定。
