来自美国罗格斯大学的研究人员发现细菌的转录起始复合物对启动子DNA进行预组装,使其适合核苷酸结合和RNA合成。这项研究为理解转录起始和转录调控提供了基础。

-2012年11月23日《科学》

中文翻译


【题目】转录起始的结构基础

【译文】在转录起始过程中,RNA聚合酶(RNAP)先结合、后松开启动子DNA,最终形成RNAP启动子开放复合物。我们鉴定到功能性转录起始复合物2.9和3.0埃分辨率的晶体结构,这个复合物由嗜热栖热菌(Thermus thermophilus)的RNA聚合酶、σA因子和启动子DNA片段,对应于转录泡和RNAP启动子开放复合物的下游双链DNA。结构分析表明σ因子通过包括拆解的相互作用,识别-10元件和鉴别元件,然后插入到三个碱基的口袋槽中,还表明RNAP通过包括拆解的相互作用,识别–4/+2区域,然后插入到+2碱基的口袋槽中。进一步研究表明,σ因子与模板链单链DNA(ssDNA)的结合对模板链ssDNA进行预组装,然后使其进入到RNAP激活中心。

英文原稿


[Title]: Structural Basis of Transcription Initiation

[Authors]:Yu Zhang, Yu Feng, Sujoy Chatterjee, Steve Tuske, Mary X. Ho, Eddy Arnold, and Richard H. Ebright

[Abstract]: During transcription initiation, RNA polymerase (RNAP) binds and unwinds promoter DNA to form an RNAP-promoter open complex. We have determined crystal structures at 2.9 and 3.0 Å resolution of functional transcription initiation complexes comprising Thermus thermophilus RNA polymerase, σA, and a promoter DNA fragment corresponding to the transcription bubble and downstream double-stranded DNA of the RNAP-promoter open complex. The structures show that σ recognizes the –10 element and discriminator element through interactions that include the unstacking and insertion into pockets of three DNA bases and that RNAP recognizes the –4/+2 region through interactions that include the unstacking and insertion into a pocket of the +2 base. The structures further show that interactions between σ and template-strand single-stranded DNA (ssDNA) preorganize template-strand ssDNA to engage the RNAP active center.

原文地址

http://www.sciencemag.org/content/338/6110/1076.abstract

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