文章基本信息

标题：X-ray crystal structure of a reiterative transcription complex reveals an atypical RNA extension pathway
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作者：Katsuhiko S. Murakami ; Yeonoh Shin ; Charles L. Turnbough 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2017
卷号：114
期号：31
页码：8211-8216
DOI：10.1073/pnas.1702741114
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Reiterative transcription is a noncanonical form of RNA synthesis in which a nucleotide specified by a single base in the DNA template is repetitively added to the nascent transcript. Here we determined the crystal structure of an RNA polymerase, the bacterial enzyme from Thermus thermophilus , engaged in reiterative transcription during transcription initiation at a promoter resembling the pyrG promoter of Bacillus subtilis . The structure reveals that the reiterative transcript detours from the dedicated RNA exit channel and extends toward the main channel of the enzyme, thereby allowing RNA extension without displacement of the promoter recognition σ-factor. Nascent transcripts containing reiteratively added G residues are eventually extended by nonreiterative transcription, revealing an atypical pathway for the formation of a transcription elongation complex.
关键词：reiterative transcription ; RNA polymerase ; X-ray crystal structure ; transcription initiation ; transcript slippage