具有完整泡状结构的大肠杆菌转录起始复合物的晶体结构
Crystal structures of the E. coli transcription initiation complexes with a complete bubble.
作者信息
Zuo Yuhong, Steitz Thomas A
机构信息
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, New Haven, CT 06510, USA; Department of Chemistry, Yale University, New Haven, CT 06520, USA.
出版信息
Mol Cell. 2015 May 7;58(3):534-40. doi: 10.1016/j.molcel.2015.03.010. Epub 2015 Apr 9.
During transcription initiation, RNA polymerase binds to promoter DNA to form an initiation complex containing a DNA bubble and enters into abortive cycles of RNA synthesis before escaping the promoter to transit into the elongation phase for processive RNA synthesis. Here we present the crystal structures of E. coli transcription initiation complexes containing a complete transcription bubble and de novo synthesized RNA oligonucleotides at about 6-Å resolution. The structures show how RNA polymerase recognizes DNA promoters that contain spacers of different lengths and reveal a bridging interaction between the 5'-triphosphate of the nascent RNA and the σ factor that may function to stabilize the short RNA-DNA hybrids during the early stage of transcription initiation. The conformation of the RNA oligonucleotides and the paths of the DNA strands in the complete initiation complexes provide insights into the mechanism that controls both the abortive and productive RNA synthesis.
在转录起始过程中，RNA聚合酶与启动子DNA结合形成包含DNA泡的起始复合物，并在逃离启动子进入延伸阶段进行持续性RNA合成之前进入RNA合成的流产循环。在此，我们展示了大肠杆菌转录起始复合物的晶体结构，其包含完整的转录泡和从头合成的RNA寡核苷酸，分辨率约为6埃。这些结构展示了RNA聚合酶如何识别包含不同长度间隔序列的DNA启动子，并揭示了新生RNA的5'-三磷酸与σ因子之间的桥连相互作用，该相互作用可能在转录起始早期稳定短RNA-DNA杂交体。完整起始复合物中RNA寡核苷酸的构象和DNA链的路径为控制流产性和生产性RNA合成的机制提供了见解。
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