Storz G, Jacobson F S, Tartaglia L A, Morgan R W, Silveira L A, Ames B N
Department of Biochemistry, University of California, Berkeley 94720.
J Bacteriol. 1989 Apr;171(4):2049-55. doi: 10.1128/jb.171.4.2049-2055.1989.
The ahp genes encoding the two proteins (F52a and C22) that make up an alkyl hydroperoxide reductase were mapped and cloned from Salmonella typhimurium and Escherichia coli. Two classes of oxidant-resistant ahp mutants which overexpress the two proteins were isolated. ahp-1 was isolated in a wild-type background and is dependent on oxyR, a positive regulator of defenses against oxidative stress. ahp-2 was isolated in an oxyR deletion background and is oxyR independent. Transposons linked to ahp-1 and ahp-2 or inserted in ahp mapped the genes to 13 min on the S. typhimurium chromosome, 59% linked to ent. Deletions of ahp obtained in both S. typhimurium and E. coli resulted in hypersensitivity to killing by cumene hydroperoxide (an alkyl hydroperoxide) and elimination of the proteins F52a and C22 from two-dimensional gels and immunoblots. ahp clones isolated from both S. typhimurium and E. coli complemented the cumene hydroperoxide sensitivity of the ahp deletion strains and restored expression of the F52a and C22 proteins. A cis-acting element required for oxyR-dependent, rpoH-independent heat shock induction of the F52a protein was present at the S. typhimurium but not the E. coli ahp locus.
编码构成烷基过氧化氢还原酶的两种蛋白质（F52a和C22）的ahp基因已从鼠伤寒沙门氏菌和大肠杆菌中进行定位和克隆。分离出了两类过表达这两种蛋白质的抗氧化剂ahp突变体。ahp - 1是在野生型背景中分离得到的，并且依赖于oxyR，后者是一种针对氧化应激防御的正调控因子。ahp - 2是在oxyR缺失背景中分离得到的，且不依赖于oxyR。与ahp - 1和ahp - 2相连或插入ahp的转座子将这些基因定位到鼠伤寒沙门氏菌染色体上的13分钟处，59%与ent相连。在鼠伤寒沙门氏菌和大肠杆菌中获得的ahp缺失导致对氢过氧化异丙苯（一种烷基过氧化氢）杀伤的超敏反应，并使二维凝胶和免疫印迹中的蛋白质F52a和C22消失。从鼠伤寒沙门氏菌和大肠杆菌中分离出的ahp克隆互补了ahp缺失菌株对氢过氧化异丙苯的敏感性，并恢复了F52a和C22蛋白质的表达。在鼠伤寒沙门氏菌而非大肠杆菌的ahp基因座上存在F52a蛋白的oxyR依赖性、rpoH非依赖性热休克诱导所需的顺式作用元件。
