A MUTANT ESCHERICHIA-COLI SIGMA-70 SUBUNIT OF RNA-POLYMERASE WITH ALTERED PROMOTER SPECIFICITY
A MUTANT ESCHERICHIA-COLI SIGMA-70 SUBUNIT OF RNA-POLYMERASE WITH ALTERED PROMOTER SPECIFICITY
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DOI：
10.1016/0022-2836(89)90567-6
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发表时间：
1989-04-20
影响因子：
5.6
通讯作者：
SUSSKIND, MM
中科院分区：
文献类型：
--
作者：
GARDELLA, T;MOYLE, H;SUSSKIND, MM
描述了改变大肠杆菌RNA聚合酶的主要σ因子σ 70的启动子特异性的突变。在携带突变型和野生型σ基因（rpoD）的菌株中，突变型σ引起突变型P22 ant启动子的活性大幅增加，其中A. T或C. G代替野生型，共有G.在位置-33处的C碱基对，该位置为共有-35六聚体5“-TTGACA-3”的第三个位置。对野生型和其他23种突变蚂蚁启动子的活性几乎没有影响，包括一种具有T. cntdot的启动子。在-33。突变的sigma也激活E。coli lac启动子与A. T或C. G，但不是T. cntdot。在相应的位置。rpoD突变（rpoD-RH 588）将CGT密码子改变为CAT。σ 70中的相应改变是Arg 588 →。他的点该残基位于大多数sigma因子中保守的区域中，该区域也与DNA结合蛋白的螺旋-转角-螺旋基序同源。这些结果表明σ 70的这个区域直接参与-35六聚体的识别。
A mutation is described that alters the promoter specificity of .sigma.70, the primary sigma factor of Escherichia coli RNA polymerase. In strains carrying both the mutant and wild-type sigma gene (rpoD), the mutant sigma causes large increase in the activity of mutant P22 ant promoters with A .cntdot. T or C .cntdot. G instead of the wild-type, consensus G .cntdot. C base-pair at position -33, the third position of the consensus - 35 hexamer 5''-TTGACA-3''. There is little or no effect on the activities of the wild-type and 23 other mutant ant promoters, including one with T .cntdot. A at -33. The mutant sigma also activates E. coli lac promoters with A .cntdot. T or C .cntdot. G, but not T .cntdot. at the corresponding position. The rpoD mutation (rpoD-RH588) changes a CGT codon to CAT. The corresponding change in .sigma.70 is Arg588 .fwdarw. His. This residue is in a region that is conserved among most sigma factors, a region that is also homologous with the helix-turn-helix motif of DNA-binding proteins. These results suggest that this region of .sigma.70 is directly involved in recognition of the -35 hexamer.