Callaci S, Heyduk E, Heyduk T
Edward A. Doisy Department of Biochemistry and Molecular Biology, Missouri 63104, USA.
Mol Cell. 1999 Feb;3(2):229-38. doi: 10.1016/s1097-2765(00)80313-5.
Luminescence resonance energy transfer measurements were used to show that binding of E. coli core RNA polymerase induced major changes in interdomain distances in the sigma 70 subunit. The simplest model describing core-induced changes in sigma 70 involves a movement of the conserved region 1 by approximately 20 A and the conserved region 4.2 by approximately 15 A with respect to conserved region 2. The core-induced movement of region 1 (autoinhibition domain) and region 4.2 (DNA-binding domain) provides structural rationale for allosteric regulation of sigma 70 DNA binding properties by the core and suggests that this regulation may not only involve directly the autoinhibition domain of sigma 70 but also could involve a modulation of spacing between DNA-binding domains of sigma 70 induced by binding of core RNAP.
荧光共振能量转移测量结果表明，大肠杆菌核心RNA聚合酶的结合会引起σ70亚基结构域间距离的重大变化。描述核心诱导的σ70变化的最简单模型涉及保守区域1相对于保守区域2移动约20埃，保守区域4.2相对于保守区域2移动约15埃。核心诱导的区域1（自抑制结构域）和区域4.2（DNA结合结构域）的移动为核心对σ70 DNA结合特性的变构调节提供了结构依据，并表明这种调节可能不仅直接涉及σ70的自抑制结构域，还可能涉及核心RNA聚合酶结合诱导的σ70 DNA结合结构域之间间距的调节。
