三联吡啶钌(Ⅲ)光敏损伤DNA的凝胶电泳研究

AN ELECTROPHORESIS STUDY OF DNA PHOTOSENSITIZATION DAMAGE BY TRIS(BIPYRIDINE) RUTHENIUM(Ⅲ)

采用琼脂糖凝胶电泳研究了以可见光引发的三联吡啶钌（Ⅲ）与 ＤＮＡ之间的光敏反应。发现在有氧气条件下，三联吡啶钌（Ⅲ）经 ４２７～４５７ｎｍ光照可导致 ＤＮＡ的光敏损伤，其途径主要是通过单线态氧与 ＤＮＡ反应引起的碱基损伤，另外则是通过 ＤＮＡ与三联吡啶钌阳离子自由基（［Ｒｕ２＋（ｂｐｙ）２（ｂｐｙ＋·）］３＋）反应导致碱基损伤而产生的，而且损伤与 ＤＮＡ和联吡啶钌之间的浓度比存在着一定关系。对照单链ＤＮＡ及双链ＤＮＡ光敏损伤结果后发现，单链ＤＮＡ较双链ＤＮＡ更易于产生光敏损伤，这可能是由于单链ＤＮＡ中碱基较双链ＤＮＡ中的更为暴露的缘故。

The photosensitization effects of tris(bipyridine)ruthenium-(Ⅲ) on DNA caused by visible light has been studied by using of agarose electrophoresis. In the presence of oxygen, it was found that DNA strand break, which amount was related to the concentration ratios of DNA and tris-(bipyridine)-ruthenium-(Ⅲ) the DNA fragments appearing induced by tris-(bipyridine)-ruthenium-(Ⅲ) irradiated with the light wavelength ranged at 427-457nm via base damage mainly resulted from the reaction of DNA with singlet oxygen, which was produced from the reaction between ground state oxygen and excite state of tris-(bipyridine)- ruthenium(Ⅲ), and via that from the reaction with cation radical of tris-(bipyridine)-ruthenium-(Ⅲ) It also shown that the ssDNA did more easily break than that of dsDNA, which might be due to the more base accessible in ssDNA.