Sigma54依赖性转录起始  

Sigma54-Dependent Transcription Initiation

作　　者：洪婷 梅子青 王丰 HONG Ting;MEI Zi-Qing;WANG Feng(School of Life Science,Beijing Institute of Technology,Key Laboratory of Molecular Medicine and Bio-diagnosis,Ministry of Industry and Information Technology,Beijing 100081,China;School of Chemistry and Biological Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京理工大学生命学院,分子医学与生物诊疗工业和信息化部重点实验室,北京100081 [2]北京科技大学化学与生物工程学院,北京100083

出　　处：《中国生物化学与分子生物学报》2022年第3期237-248,共12页Chinese Journal of Biochemistry and Molecular Biology

基　　金：国家自然科学基金(No.31870791)资助。

摘　　要：作为细菌RNA聚合酶(RNAP)的组成型辅助因子,sigma70和sigma54分别参与了原核细胞不同类型基因的转录起始调控。sigma70负责管家基因的自发转录起始;而sigma54负责应激信号相关的基因转录起始。sigma54与RNAP形成复合物后,会通过空间阻滞的方式阻碍DNA进入RNAP中,抑制基因转录起始。当细胞环境变化后,特定应激信号会通过细菌增强子结合蛋白(bEBP)诱发sigma54的构象发生变化,解除sigma54对RNAP的抑制,启动sigma54依赖的基因转录。最近的结构生物学研究揭示了sigma54依赖性转录起始的若干复合物结构,包括全酶、封闭式复合物、2个中间状态复合物及开放式复合物。通过分析这些转录起始复合物的结构,本文阐述了转录起始过程中复合物的结构变化。描述并分析了sigma54和bEBP在转录起始过程中所发挥的功能。本文有助于了解转录起始分子水平的变化,为深入理解sigma54和bEBP促进转录起始的分子机制提供了参考。As constitutive cofactors of bacterial RNA polymerase(RNAP),sigma70 and sigma54 are involved in the regulation of transcription initiation for different genes in prokaryotic cells,respectively.sigma70 is responsible for the spontaneous transcription initiation of housekeeping genes,while sigma54 blocks DNA from entering RNAP by way of steric blockade and inhibits the initiation of gene transcription after forming a complex with RNAP.When the cell environment changes,specific stress signals will induce conformational changes of sigma54 through the bacterial enhancer binding protein(bEBP),release the inhibition of sigma54 on RNAP,and initiate sigma54-dependent gene transcription.Recent structural biology studies have revealed the structures of several complexes for sigma54-dependent transcription initiation,including holoenzyme,closed complex,two intermediate complexes and open complex.By analyzing the structure of these transcription initiation complexes,we introduce the structural changes of the complex during transcription initiation in this article.The functions of sigma54 and bEBP in the process of transcription initiation are described and analyzed.This article is helpful to understand the changes of transcription initiation on molecular level,and provides a reference for deep understanding of the molecular mechanism of sigma54 and bEBP in promoting transcription initiation.

关 键 词：转录调控 sigma54 细菌增强子激活蛋白质 转录起始复合物 RNA聚合酶 

分 类 号：Q71[生物学—分子生物学]