Basis for recognition of cisplatin-modified DNA by high-mobility-group proteins
Basis for recognition of cisplatin-modified DNA by high-mobility-group proteins
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DOI：
10.1038/21460
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发表时间：
1999-06-17
期刊：
影响因子：
64.8
通讯作者：
Lippard, SJ
中科院分区：
文献类型：
--
作者：
Ohndorf, UM;Rould, MA;Lippard, SJ
顺式二胺二氯铂（II）（顺铂）的抗癌活性源于其损伤DNA的能力，其形成的主要加合物是链内d（GpG）和d（ApG）交联(1)。这些交联使双链弯曲或展开，改变后的结构吸引高迁移基结构域（HMG）和其他蛋白质(2)。hmg结构域蛋白与顺铂修饰dna的结合被认为介导了药物的抗肿瘤特性（3,4）。许多hmg结构域蛋白识别改变的DNA结构，如四向连接和顺铂修饰的DNA(5)，但直到现在，这种识别的分子基础尚不清楚。在这里，我们描述诱变，羟基自由基足迹和x射线研究，阐明了1:1的结构。顺铂修饰的DNA/ hmg结构域复合物HMG1的结构域A与含有位点特异性顺式-[Pt(NH3)(2){d(GpG)- n7 (1),- n7(2)}]加合物的16碱基对DNA双链的加宽小槽结合，DNA在铂-DNA交联上产生的疏水缺口处强烈结结，蛋白质结合仅延伸到铂化链的3'侧。第37位的苯丙氨酸残基插入到铂交联d（GpG）位点上的疏水缺口中，在丙氨酸取代苯丙氨酸的突变体中，该结构域的结合显著减少。
The anticancer activity of cis-diamminedichloroplatinum(II) (cisplatin) arises from its ability to damage DNA, with the major adducts formed being intrastrand d(GpG) and d(ApG) crosslinks(1). These-crosslinks bend and unwind the duplex, and the altered structure attracts high-mobility-group domain (HMG) and other proteins(2). This binding of HMG-domain proteins to cisplatin-modified DNA-has been postulated to mediate the antitumour properties of the drug(3,4). Many HMG-domain proteins recognize altered DNA structures such as four-way junctions and cisplatin-modified DNA(5), but until now:the molecular basis for this recognition was unknown. Here we describe mutagenesis, hydroxyl-radical footprinting and X-ray studies that elucidate the structure of a 1:1. cisplatin-modified DNA/HMG-domain complex Domain A of the structure-specific HMG-domain protein HMG1 binds to the widened minor groove of a 16-base-pair DNA duplex containing a site-specific cis-[Pt(NH3)(2){d(GpG)-N7(1),-N7(2)}] adduct, The DNA is strongly kinked at a hydrophobic notch created at the platinum-DNA crosslink and protein binding extends exclusively to the 3' side of the platinated strand. A phenylalanine residue at position 37 intercalates into a hydrophobic notch created at the platinum crosslinked d(GpG) site and binding of the domain is dramatically reduced in a mutant in which alanine is substituted for phenylalanine at this position.