Saijo M, Kuraoka I, Masutani C, Hanaoka F, Tanaka K
Division of Cellular Genetics, Institute for Molecular and Cellular Biology, Osaka University, Japan.
Nucleic Acids Res. 1996 Dec 1;24(23):4719-24. doi: 10.1093/nar/24.23.4719.
Recent studies have shown that many proteins are involved in the early steps of nucleotide excision repair and that there are some interactions between nucleotide excision repair proteins, suggesting that these interactions are important in the reaction mechanism. The xeroderma pigmentosum group A protein (XPA) was shown to bind to the replication protein A (RPA) or the excision repair cross complementing rodent repair deficiency group 1 protein (ERCC1), and these interactions might be involved in the damage-recognition and/or incision steps, of nucleotide excision repair. Here we show that the XPA regions required for the binding to the 70 and 34 kDa subunits of RPA are located in the middle and on N-terminal regions of XPA, respectively. These regions do not overlap with the ERCC1-binding region of XPA, and a ternary protein complex of RPA, XPA and ERCC1 was detected in vitro. In addition, using the surface plasmon resonance biosensor, the binding of RPA and ERCC1 to XPA was investigated. The dissociation constants (KD) of RPA and ERCC1 with XPA were 1.9 x 10(-8 )and 2.5 x 10(-7) M, respectively. Moreover, our results suggest the sequential binding of RPA and ERCC1 to XPA.
最近的研究表明，许多蛋白质参与核苷酸切除修复的早期步骤，并且核苷酸切除修复蛋白之间存在一些相互作用，这表明这些相互作用在反应机制中很重要。已证明着色性干皮病A组蛋白（XPA）与复制蛋白A（RPA）或切除修复交叉互补啮齿动物修复缺陷组1蛋白（ERCC1）结合，并且这些相互作用可能参与核苷酸切除修复的损伤识别和/或切割步骤。在此我们表明，XPA与RPA的70 kDa和34 kDa亚基结合所需的区域分别位于XPA的中间区域和N端区域。这些区域与XPA的ERCC1结合区域不重叠，并且在体外检测到RPA、XPA和ERCC1的三元蛋白复合物。此外，使用表面等离子体共振生物传感器研究了RPA和ERCC1与XPA的结合。RPA和ERCC1与XPA的解离常数（KD）分别为1.9×10^(-8)和2.5×10^(-7) M。此外，我们的结果表明RPA和ERCC1与XPA的顺序结合。
