Seeley T W, Grossman L
Department of Biochemistry, School of Hygiene and Public Health, Johns Hopkins University, Maryland 21205.
J Biol Chem. 1990 May 5;265(13):7158-65.
The role of UvrB in determining the nucleotide dependence of Escherichia coli excision repair has been investigated. The mutation of lysine 45 in the ATPase motif of UvrB to alanine leads to an acute defect in ATP hydrolysis and failure to support incision of UV-damaged DNA. This ATP hydrolysis activity is not required for interaction of UvrB with UvrA in solution, or for formation of a damage-independent nucleoprotein complex in the presence of UvrA and nucleotide. This UvrB mutant fails, however, to support damage-specific nucleoprotein complex formation, and does not participate in a UvrA-UvrB-dependent helicase-like activity. We conclude from these results that mutation at lysine 45 in the ATPase motif of UvrB specifically inhibits a key step in nucleotide excision repair involving the UvrB ATPase-dependent translocation of nucleoprotein complexes from undamaged to damaged DNA sites.
人们已经研究了UvrB在确定大肠杆菌切除修复的核苷酸依赖性方面的作用。UvrB的ATP酶基序中赖氨酸45突变为丙氨酸会导致ATP水解出现严重缺陷，并且无法支持对紫外线损伤的DNA进行切割。这种ATP水解活性对于溶液中UvrB与UvrA的相互作用，或在存在UvrA和核苷酸的情况下形成与损伤无关的核蛋白复合物而言并非必需。然而，这种UvrB突变体无法支持损伤特异性核蛋白复合物的形成，并且不参与UvrA-UvrB依赖性解旋酶样活性。我们从这些结果得出结论，UvrB的ATP酶基序中赖氨酸45处的突变特异性地抑制了核苷酸切除修复中的一个关键步骤，该步骤涉及UvrB依赖ATP的核蛋白复合物从未受损DNA位点向受损DNA位点的易位。
