RapA的结构，一种在转录过程中使RNA聚合酶循环利用的Swi2/Snf2蛋白。
Structure of RapA, a Swi2/Snf2 protein that recycles RNA polymerase during transcription.
作者信息
Shaw Gary, Gan Jianhua, Zhou Yan Ning, Zhi Huijun, Subburaman Priadarsini, Zhang Rongguang, Joachimiak Andrzej, Jin Ding Jun, Ji Xinhua
机构信息
Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA.
出版信息
Structure. 2008 Sep 10;16(9):1417-27. doi: 10.1016/j.str.2008.06.012.
RapA, as abundant as sigma70 in the cell, is an RNA polymerase (RNAP)-associated Swi2/Snf2 protein with ATPase activity. It stimulates RNAP recycling during transcription. We report a structure of RapA that is also a full-length structure for the entire Swi2/Snf2 family. RapA contains seven domains, two of which exhibit novel protein folds. Our model of RapA in complex with ATP and double-stranded DNA (dsDNA) suggests that RapA may bind to and translocate on dsDNA. Our kinetic template-switching assay shows that RapA facilitates the release of sequestered RNAP from a posttranscrption/posttermination complex for transcription reinitiation. Our in vitro competition experiment indicates that RapA binds to core RNAP only but is readily displaceable by sigma70. RapA is likely another general transcription factor, the structure of which provides a framework for future studies of this bacterial Swi2/Snf2 protein and its important roles in RNAP recycling during transcription.
RapA在细胞中的含量与σ70一样丰富，是一种与RNA聚合酶（RNAP）相关的具有ATP酶活性的Swi2/Snf2蛋白。它在转录过程中刺激RNAP循环利用。我们报道了RapA的一种结构，这也是整个Swi2/Snf2家族的全长结构。RapA包含七个结构域，其中两个呈现出新颖的蛋白质折叠方式。我们构建的RapA与ATP和双链DNA（dsDNA）复合物的模型表明，RapA可能结合在dsDNA上并在其上移位。我们的动力学模板转换试验表明，RapA有助于将被隔离的RNAP从转录后/终止后复合物中释放出来，以便重新启动转录。我们的体外竞争实验表明，RapA仅与核心RNAP结合，但很容易被σ70取代。RapA可能是另一种通用转录因子，其结构为今后研究这种细菌Swi2/Snf2蛋白及其在转录过程中RNAP循环利用中的重要作用提供了一个框架。
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