[溴化乙锭和柔红霉素嵌入DNA中的体积效应及压缩性变化]

[Volume effect and change in compressibility in intercalation of ethidium bromide and daunomycin in DNA].

作者信息

Kudriashov E D, Bukin V A, Braginskaia F I, Marky L A

机构信息

Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia.

出版信息

Biofizika. 1998 Jan-Feb;43(1):40-5.

PMID:9567175

Abstract

A combination of high-precision and density techniques was used to investigate the binding of ethidium bromide and daunomycin to DNA. It was shown that intercalation is accompanied by a decrease in apparent volume and adiabatic compressibility of DNA, which were -28 cm3mol-1 and -20.10(-4) cm3mol-1bar-1 for binding of ethidium to DNA, and -28 cm3mol-1 and -18.10(-4) cm3mol-1bar-1 for daunomycin, respectively. The values obtained have been compared with those of the hydration contributions of atomic groups to the apparent molar volume and apparent molar compressibility of the ligands as well as the contribution of intrinsic compressibility of DNA. The volume effects in the intercalation of ligands correspond to the values expected for the dehydration of aromatic heterocyclic rings. On other hand, negative compressibility changes may be explained by a decrease of the intrinsic compressibility of DNA and possible increase of its hydration as result of conformational changes upon ligand binding.

摘要

采用高精度和密度技术相结合的方法研究了溴化乙锭和柔红霉素与DNA的结合。结果表明，嵌入过程伴随着DNA表观体积和绝热压缩性的降低，溴化乙锭与DNA结合时，表观体积和绝热压缩性分别为-28 cm³mol⁻¹和-20×10⁻⁴ cm³mol⁻¹bar⁻¹，柔红霉素与DNA结合时分别为-28 cm³mol⁻¹和-18×10⁻⁴ cm³mol⁻¹bar⁻¹。将所得值与原子基团对配体表观摩尔体积和表观摩尔压缩性的水化贡献值以及DNA固有压缩性的贡献值进行了比较。配体嵌入过程中的体积效应与芳香杂环脱水预期值相符。另一方面，负压缩性变化可能是由于DNA固有压缩性降低以及配体结合后构象变化导致其水化作用可能增加所致。