Structure of the bacterial RNA polymerase promoter specificity σ subunit
Structure of the bacterial RNA polymerase promoter specificity σ subunit
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DOI：
10.1016/s1097-2765(02)00470-7
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发表时间：
2002-03-01
期刊：
影响因子：
16
通讯作者：
Darst, SA
中科院分区：
文献类型：
--
作者：
Campbell, EA;Muzzin, O;Darst, SA
sigma亚基是细菌转录的关键调节因子。在结晶过程中原位发生的水生栖热菌sigma（A）的蛋白水解揭示了通过柔性连接体连接的三个结构域sigma（2）、sigma（3）和sigma（4）。测定每个结构域的晶体结构，以及与~ 35个元素DNA复合的σ（4）的晶体结构。每个结构域的暴露表面对于RNA聚合酶结合是重要的。对于-10元件识别和解链重要的普遍保守的残基位于sigma的一个面上（2），而对于扩展的-10识别重要的残基位于sigma上（3）。遗传学研究正确地预测了sigma（4）中的螺旋-转角-螺旋基序识别-35元件，但不识别蛋白质-DNA相互作用的细节。sigma（4）中的阳性对照突变体聚集在两个区域中，定位成与恰好在-35元件的上游或下游结合的激活剂相互作用。
The sigma subunit is the key regulator of bacterial transcription. Proteolysis of Thermus aquaticus sigma(A), which occurred in situ during crystallization, reveals three domains, sigma(2), sigma(3), and sigma(4), connected by flexible linkers. Crystal structures of each domain were determined, as well as Of sigma(4) complexed with -35 element DNA. Exposed surfaces of each domain are important for RNA polymerase binding. Universally conserved residues important for -10 element recognition and melting lie on one face Of sigma(2), while residues important for extended -10 recognition lie on sigma(3). Genetic studies correctly predicted that a helix-turn-helix motif in sigma(4) recognizes the -35 element but not the details of the protein-DNA interactions. Positive control mutants in sigma(4) cluster in two regions, positioned to interact with activators bound just upstream or downstream of the -35 element.