Communication between Eσ54, promoter DNA and the conserved threonine residue in the GAFTGA motif of the PspF σ54-dependent activator during transcription activation
Communication between Eσ54, promoter DNA and the conserved threonine residue in the GAFTGA motif of the PspF σ54-dependent activator during transcription activation
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DOI：
10.1111/j.1365-2958.2004.04280.x
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发表时间：
2004-10-01
影响因子：
3.6
通讯作者：
Buck, M
中科院分区：
文献类型：
--
作者：
Bordes, P;Wigneshweraraj, SR;Buck, M
Esigma(54) 封闭启动子复合物向开放启动子复合物的转化需要专门的激活剂，这些激活剂是 AAA（与各种细胞活动相关的 ATP 酶）蛋白家族的成员。 Esigma(54) 激活剂的 ATP 结合和水解活性用于能量耦合反应，以重塑 Esigma(54) 闭合启动子复合物并克服 sigma(54) 对开放复合物形成施加的阻碍。 Esigma(54) 封闭复合体中 AAA 激活剂的重塑靶标包括由 sigma(54) 区域 I 贡献的复杂界面、核心 RNA 聚合酶和启动子 DNA 叉连接结构，构成 Esigma(54) 调控中心。 Esigma(54) 激活剂上的一个 sigma(54) 结合表面是一个保守序列，称为 GAFTGA 基序。在这里，我们详细描述了 sigma(54) 区域 I 与大肠杆菌 AAA sigma(54) 激活剂噬菌体休克蛋白 F 之间的相互作用。使用模拟开放复合物形成过程中 DNA 采用的不同构象的 Esigma(54) 启动子复合物，我们研究了 GAFTGA 基序中保守的苏氨酸残基对转录激活的贡献。我们的结果表明，Esigma(54) 调控中心的组织，特别是 sigma(54) 区域 I 所采用的构象和开放复合物形成过程中的 DNA 叉连接结构，通过 GAFTGA 基序的保守 T 残基与 AAA 激活剂通讯。
Conversion of Esigma(54) closed promoter complexes to open promoter complexes requires specialized activators which are members of the AAA (ATPases Associated with various cellular Activities) protein family. The ATP binding and hydrolysis activity of Esigma(54) activators is used in an energy coupling reaction to remodel the Esigma(54) closed promoter complex and to overcome the sigma(54)-imposed block on open complex formation. The remodelling target for the AAA activator within the Esigma(54) closed complex includes a complex interface contributed to by Region I of sigma(54), core RNA polymerase and a promoter DNA fork junction structure, comprising the Esigma(54) regulatory centre. One sigma(54) binding surface on Esigma(54) activators is a conserved sequence known as the GAFTGA motif. Here, we present a detailed characterization of the interaction between Region I of sigma(54) and the Escherichia coli AAA sigma(54) activator Phage shock protein F. Using Esigma(54) promoter complexes that mimic different conformations adopted by the DNA during open complex formation, we investigated the contribution of the conserved threonine residue in the GAFTGA motif to transcription activation. Our results suggest that the organization of the Esigma(54) regulatory centre, and in particular the conformation adopted by the sigma(54) Region I and the DNA fork junction structure during open complex formation, is communicated to the AAA activator via the conserved T residue of the GAFTGA motif.