Kuemmerle N B, Masker W E
J Bacteriol. 1980 May;142(2):535-46. doi: 10.1128/jb.142.2.535-546.1980.
A pair of related Escherichia coli K-12 strains, one of which contains the uvrD101 mutation, were constructed and compared for ability to perform various steps in the excision repair of deoxyribonucleic acid damage inflicted by ultraviolet radiation. The results of this study indicated: (i) ultraviolet sensitivity in the uvrD101 mutant was greater than that of wild type but less than that measured in an incision-deficient uvrA mutant; (ii) host cell reactivation paralleled the survival data; (iii) postirradiation deoxyribonucleic acid degradation was virtually identical in the two strains; (iv) incision, presumably at the sites of pyrimidine dimers, proceeded normally in the uvrD101 strain; (v) excision of pyrimidine dimers was markedly reduced in both rate and extent in the uvrD101 mutant; (vi) the amount of repair resynthesis was the same in both strains, and there was no evidence of abnormally long repair patches in the uvrD mutant; and (vii) rejoining of incision breaks was slow and incomplete in the uvrD strain. These data suggest that the ultraviolet sensitivity conferred by the uvrD mutation arises from inefficient removal of pyrimidine dimers or from failure to close incision breaks. The data are compatible with the notion that the uvrD+ gene produce affects the conformation of incised deoxyribonucleic acid molecules.
构建了一对相关的大肠杆菌K - 12菌株，其中一个含有uvrD101突变，比较它们在修复紫外线造成的脱氧核糖核酸损伤的各个步骤中的能力。本研究结果表明：(i)uvrD101突变体对紫外线的敏感性高于野生型，但低于切口缺陷型uvrA突变体；(ii)宿主细胞复活与存活数据平行；(iii)照射后脱氧核糖核酸降解在两种菌株中几乎相同；(iv)推测在嘧啶二聚体位点的切口在uvrD101菌株中正常进行；(v)uvrD101突变体中嘧啶二聚体的切除在速率和程度上均显著降低；(vi)两种菌株中修复再合成的量相同，且在uvrD突变体中没有异常长的修复片段的证据；(vii)uvrD菌株中切口断裂的重新连接缓慢且不完全。这些数据表明，uvrD突变赋予的紫外线敏感性源于嘧啶二聚体去除效率低下或切口断裂未能闭合。这些数据与uvrD +基因产物影响切口脱氧核糖核酸分子构象的观点一致。
