EFFECTS OF AMINO-ACID SUBSTITUTIONS IN THE -10 BINDING REGION OF SIGMA(E) FROM BACILLUS-SUBTILIS
EFFECTS OF AMINO-ACID SUBSTITUTIONS IN THE -10 BINDING REGION OF SIGMA(E) FROM BACILLUS-SUBTILIS
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DOI：
10.1128/jb.174.21.6815-6821.1992
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发表时间：
1992-11-01
影响因子：
3.2
通讯作者：
MORAN, CP
中科院分区：
文献类型：
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作者：
JONES, CH;TATTI, KM;MORAN, CP
细菌RNA聚合酶的σ亚基是与启动子特异性结合所必需的。大多数σ因子中的一个区域在其同源启动子的-10区域处进行序列特异性接触。为了测试氨基酸在该-10结合区域中的作用，我们检查了来自枯草芽孢杆菌的sigma（E）中的49个单氨基酸取代的影响。我们测定了每个氨基酸取代对孢子形成的影响，因为σ（E）对于B中的内生孢子形成是必需的。枯草芽孢杆菌我们的结果表明，在几个位置，包括高度保守的芳香族氨基酸在位置102的取代，有很少或没有检测到的影响。在另一个位置，位置117的取代，产生显性负突变，我们认为，这些突变允许RNA聚合酶含有突变体σ因子特异性结合启动子，但阻止转录起始。在隐性缺陷等位基因中，在位置113、115和120处产生取代的那些等位基因产生最有缺陷的σ因子。这些结果表明野生型sigma（E）中这些位置处或附近的残基在sigma（E）功能中起重要作用。
The sigma subunit of bacterial RNA polymerase is required for specific binding to promoters. One region in most sigma factors makes sequence-specific contacts at the -10 region of its cognate promoters. To test the role of the amino acids in this -10 binding region, we examined the effects of 49 single-amino-acid substitutions in sigma(E) from Bacillus subtilis. We assayed the effect of each amino acid substitution on spore formation because sigma(E) is essential for endospore formation in B. subtilis. Our results showed that substitutions at several positions, including the highly conserved aromatic amino acid at position 102, had little or no detectable effect. Substitutions at another position, position 117, produced dominant negative mutations; we suggest that these mutations allow RNA polymerase containing the mutant sigma factor to bind specifically to promoters but prevent transcription initiation. Of the recessive defective alleles, those that produced substitutions at positions 113, 115, and 120 produced the most defective sigma factors. These results suggest that the residues at or near these positions in wild-type sigma(E) play important roles in sigma(E) function.