用荧光探针研究铂配合物与核小体的相互作用。

The interaction of platinum complexes with nucleosomes investigated with fluorescent probes.

作者信息

Thompson L M, Arquilla M, Simpkins H

出版信息

Biochim Biophys Acta. 1982 Aug 30;698(2):173-82. doi: 10.1016/0167-4781(82)90133-6.

Abstract

The fluorescent probes, N,-(3-pyrene)maleimide, which is specific for histone H3, and terbium (Tb3+), which is specific for guanine single-stranded residues in DNA, are used to investigate the interaction of platinum complexes (cis- and trans-dichlorodiammineplatinum(II)) with rat liver and calf thymus nucleosomes. At low concentrations of the drug, lower than most of those reported previously in studies investigating the interaction of the drugs with isolated DNA, N-(3-pyrene)maleimide studies show that profound modifications occur near or in the cysteinyl binding site of histone H3. H3 dimer formation appears to be the cause of the change induced by trans-DDP; however, the effects observed with the cis-isomer do not seem to be correlated with dimer formation. At short incubation times, Tb3+ fluorescence shows small changes in DNA conformation, but they are slight when compared to the effect observed with proteins at the same length of incubation. SDS-polyacrylamide gels indicate some changes in protein composition, and agarose gels display a decrease in ethidium bromide staining of the cis-treated DNA. The results suggest that the protein portion, predominantly histone H3, as well as DNA are targets for the platinum derivatives in the nucleosome.

摘要

荧光探针N,-(3-芘)马来酰亚胺（对组蛋白H3具有特异性）和铽（Tb3+，对DNA中的鸟嘌呤单链残基具有特异性）被用于研究铂配合物（顺式和反式二氯二氨铂(II)）与大鼠肝脏和小牛胸腺核小体的相互作用。在药物浓度低于之前大多数研究药物与分离DNA相互作用时所报道的浓度时，N-(3-芘)马来酰亚胺研究表明，在组蛋白H3的半胱氨酰结合位点附近或位点处发生了深刻的修饰。H3二聚体的形成似乎是反式顺铂诱导变化的原因；然而，顺式异构体所观察到的效应似乎与二聚体的形成无关。在短孵育时间内，Tb3+荧光显示DNA构象有微小变化，但与相同孵育时间下蛋白质所观察到的效应相比，这些变化很轻微。SDS-聚丙烯酰胺凝胶表明蛋白质组成有一些变化，琼脂糖凝胶显示顺式处理的DNA的溴化乙锭染色减少。结果表明，主要是组蛋白H3的蛋白质部分以及DNA都是核小体中铂衍生物的作用靶点。