Escherichia coli RNA polymerase-associated SWI/SNF protein RapA: evidence for RNA-directed binding and remodeling activity.
Escherichia coli RNA polymerase-associated SWI/SNF protein RapA: evidence for RNA-directed binding and remodeling activity.
复制标题
DOI：
10.1093/nar/gkm747
复制
发表时间：
2007
影响因子：
14.9
通讯作者：
Sukhodolets, Maxim V
中科院分区：
文献类型：
--
作者：
McKinley, Brian A;Sukhodolets, Maxim V
解旋酶样SWI/SNF蛋白存在于从细菌到人类的遥远生物中，表明它们执行非常基本和普遍存在的核酸管理形式；目前的研究将SWI/SNF蛋白的活性与DNA和DNA -蛋白复合物的重塑联系起来。细菌SWI/SNF同系物rapa是大肠杆菌RNA聚合酶复合物的组成部分，与终止后DNA-RNA聚合酶- RNA三元复合物（PTC）的重塑有关，但其明确的核酸底物和机制尚不清楚。我们的工作提供了证据表明RNA是RapA的关键底物。具体来说，在转录过程中稳定的RapA - RNA中间体的形成以及本文提出的其他独立证据表明，RapA在转录过程中结合并重塑RNA。我们的结果与RapA促进DNA-RNA聚合酶- RNA三元复合物的RNA释放一致；这一过程可能伴随着非标准DNA-RNA复合物（假定的DNA-RNA三重体）的不稳定。综上所述，我们的数据表明RapA具有新的RNA重塑活性，RapA是SWI/SNF蛋白超家族的代表。
Helicase-like SWI/SNF proteins are present in organisms belonging to distant kingdoms from bacteria to humans, indicating that they perform a very basic and ubiquitous form of nucleic acid management; current studies associate the activity of SWI/SNF proteins with remodeling of DNA and DNA–protein complexes. The bacterial SWI/SNF homolog RapA—an integral part of the Escherichia coli RNA polymerase complex—has been implicated in remodeling post-termination DNA–RNA polymerase–RNA ternary complexes (PTC), however its explicit nucleic acid substrates and mechanism remain elusive. Our work presents evidence indicating that RNA is a key substrate of RapA. Specifically, the formation of stable RapA–RNA intermediates in transcription and other, independent lines of evidence presented herein indicate that RapA binds and remodels RNA during transcription. Our results are consistent with RapA promoting RNA release from DNA–RNA polymerase–RNA ternary complexes; this process may be accompanied by the destabilization of non-canonical DNA–RNA complexes (putative DNA–RNA triplexes). Taken together, our data indicate a novel RNA remodeling activity for RapA, a representative of the SWI/SNF protein superfamily.