UvrB及其蛋白水解产物UvrB*的隐秘ATP酶活性参与DNA修复。

Caron P R, Grossman L

Department of Biochemistry, The Johns Hopkins University, School of Hygiene and Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA.

Nucleic Acids Res. 1988 Oct 25;16(20):9651-62. doi: 10.1093/nar/16.20.9651.

The incision of damaged DNA by the Escherichia coli UvrABC endonuclease requires ATP hydrolysis. Although the deduced sequence of the UvrB protein suggests a putative ATP binding site, no nucleoside triphosphatase activity is demonstrable with the purified UvrB protein. The UvrB protein is specifically proteolyzed in E. coli cell extracts to yield a 70 kD fragment, referred to as UvrB*, which has been purified and is shown to possess a single-strand DNA dependent ATPase activity. Substrate specificity and kinetic analyses of UvrB* catalyzed nucleotide hydrolysis indicate that the stimulation in DNA dependent ATPase activity following formation of the UvrAB complex results from the activation of the normally sequestered UvrB associated ATPase. Using nucleotide analogues, it can be shown that this activity is essential to the DNA incision reaction carried out by the UvrABC complex.

大肠杆菌UvrABC核酸内切酶对受损DNA的切割需要ATP水解。尽管UvrB蛋白的推导序列显示有一个假定的ATP结合位点，但纯化的UvrB蛋白未表现出核苷三磷酸酶活性。UvrB蛋白在大肠杆菌细胞提取物中被特异性蛋白酶解，产生一个70 kD的片段，称为UvrB*，它已被纯化并显示具有单链DNA依赖性ATP酶活性。对UvrB*催化的核苷酸水解的底物特异性和动力学分析表明，UvrAB复合物形成后DNA依赖性ATP酶活性的刺激是由于正常被隔离的与UvrB相关的ATP酶的激活。使用核苷酸类似物可以表明，这种活性对于UvrABC复合物进行的DNA切割反应至关重要。