Sundin G W, Kidambi S P, Ullrich M, Bender C L
Department of Microbiology and Immunology, University of Illinois-Chicago 60612, USA.
Gene. 1996 Oct 24;177(1-2):77-81. doi: 10.1016/0378-1119(96)00273-9.
The indigenous plasmids, pPSR1 and pPSR5, were each shown to confer resistance to ultraviolet light (UV) in Pseudomonas syringae (Ps) pv. syringae FF5. The UV-resistance (UVR) determinant was subcloned from a cosmid library of pPSR1, and sequence analysis revealed the presence of two ORFs, designated rulAB which are homologous to the Escherichia coli umuDC mutagenic DNA repair systems and other plasmid-encoded UVR operons. Amino acid (aa) alignments indicated that RulAB are most closely related to the RumAB proteins from plasmid R391, sharing 40.5% and 48.6% aa identity with RumA and RumB, respectively. UV sensitivity assays with the cloned rulAB genes indicated that the expression of UVR in Ps required a functional recA gene.
研究表明，本地质粒pPSR1和pPSR5可使丁香假单胞菌丁香致病变种FF5对紫外线（UV）产生抗性。从pPSR1的黏粒文库中对紫外线抗性（UVR）决定簇进行亚克隆，序列分析显示存在两个开放阅读框（ORF），命名为rulAB，它们与大肠杆菌umuDC诱变DNA修复系统及其他质粒编码的UVR操纵子同源。氨基酸（aa）序列比对表明，RulAB与质粒R391的RumAB蛋白关系最为密切，分别与RumA和RumB共享40.5%和48.6%的氨基酸序列一致性。对克隆的rulAB基因进行的紫外线敏感性测定表明，丁香假单胞菌中UVR的表达需要一个功能性recA基因。
