Structure of a complex between E. coli DNA topoisomerase I and single-stranded DNA
Structure of a complex between E. coli DNA topoisomerase I and single-stranded DNA
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DOI：
10.1016/j.str.2003.09.013
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发表时间：
2003-11-01
期刊：
影响因子：
5.7
通讯作者：
Mondragón, A
中科院分区：
文献类型：
--
作者：
Perry, K;Mondragón, A
为了深入了解大肠杆菌DNA拓扑异构酶I与ssDNA结合和识别的机制，解析了拓扑异构酶I的67 kDa N-末端片段与ssDNA的复合物的结构。该结构揭示了IA型拓扑异构酶的多步催化循环中的一个新的构象阶段。在该结构中，通向活性位点的ssDNA结合沟被占据，但活性位点没有完全形成。没有看到大的构象变化;相反，平行于ssDNA结合槽的单螺旋移位以夹住ssDNA。该结构有助于澄清构象事件的时间序列，从最初的空酶开始，并进行到单链DNA占据和催化活性位点。
In order to gain insights into the mechanism of ssDNA binding and recognition by Escherichia coli DNA topoisomerase I, the structure of the 67 kDa N-terminal fragment of topoisomerase I was solved in complex with ssDNA. The structure reveals a new conformational stage in the multistep catalytic cycle of type IA topoisomerases. In the structure, the ssDNA binding groove leading to the active site is occupied, but the active site is not fully formed. Large conformational changes are not seen; instead, a single helix parallel to the ssDNA binding groove shifts to clamp the ssDNA. The structure helps clarify the temporal sequence of conformational events, starting from an initial empty enzyme and proceeding to a ssDNA-occupied and catalytically competent active site.