T7 RNA聚合酶
抄写(语言学)
RNA聚合酶
延伸率
核糖核酸
RNA聚合酶Ⅱ
DNA
生物物理学
聚合酶
螺旋(腹足类)
生物
化学
分子生物学
结晶学
发起人
噬菌体
生物化学
基因
基因表达
材料科学
生态学
语言学
哲学
大肠杆菌
极限抗拉强度
蜗牛
冶金
作者
Kimberly Durniak,Scott Bailey,Thomas A. Steitz
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:2008-10-23
卷期号:322 (5901): 553-557
被引量:132
标识
DOI:10.1126/science.1163433
摘要
Structural studies of the T7 bacteriophage DNA-dependent RNA polymerase (T7 RNAP) have shown that the conformation of the amino-terminal domain changes substantially between the initiation and elongation phases of transcription, but how this transition is achieved remains unclear. We report crystal structures of T7 RNAP bound to promoter DNA containing either a 7- or an 8-nucleotide (nt) RNA transcript that illuminate intermediate states along the transition pathway. The amino-terminal domain comprises the C-helix subdomain and the promoter binding domain (PBD), which consists of two segments separated by subdomain H. The structures of the intermediate complex reveal that the PBD and the bound promoter rotate by ∼45° upon synthesis of an 8-nt RNA transcript. This allows the promoter contacts to be maintained while the active site is expanded to accommodate a growing heteroduplex. The C-helix subdomain moves modestly toward its elongation conformation, whereas subdomain H remains in its initiation- rather than its elongation-phase location, more than 70 angstroms away.
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