A domain insertion in Escherichia coli GyrB adopts a novel fold that plays a critical role in gyrase function.
A domain insertion in Escherichia coli GyrB adopts a novel fold that plays a critical role in gyrase function.
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DOI：
10.1093/nar/gkq665
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发表时间：
2010-11
影响因子：
14.9
通讯作者：
Berger JM
中科院分区：
文献类型：
--
作者：
Schoeffler AJ;May AP;Berger JM
DNA拓扑异构酶管理着所有生命形式中的染色体超螺旋和组织。旋转酶是一种原核异四聚体型IIA拓扑酶，通过依赖于ATP的链传递机制将负超螺旋引入DNA。所有的旋转酶同源基因都依赖于一组同源的催化结构域来发挥功能；然而，这些酶也可以拥有物种特定的辅助区。许多革兰氏阴性细菌的旋转酶在GyrB亚单位的金属和DNA结合的TOPRIM结构域中含有一个170个氨基酸的插入，结构和功能未知。我们已经确定了含有该插入片段的212 kDa大肠杆菌旋转酶DNA结合和切割核心的结构，分辨率为3.1 á。我们发现插入物采用了一种新颖的延伸折叠，将gyrB TOPRIM结构域支撑在其伴侣gyrA亚基的卷曲线圈臂上。结构导向的插入片段的缺失大大降低了DNA结合、超螺旋和DNA刺激的旋转酶的ATPase活性。插入片段和GyrA之间接触点的单个氨基酸的突变对超螺旋和ATP周转的影响更小，并且不影响DNA结合。我们的数据表明，该插入物具有两个功能，一是作为空间堡垒预先配置主要DNA结合位点，二是作为继电器帮助协调不同功能结构域之间的通信。
DNA topoisomerases manage chromosome supercoiling and organization in all forms of life. Gyrase, a prokaryotic heterotetrameric type IIA topo, introduces negative supercoils into DNA by an ATP-dependent strand passage mechanism. All gyrase orthologs rely on a homologous set of catalytic domains for function; however, these enzymes also can possess species-specific auxiliary regions. The gyrases of many gram-negative bacteria harbor a 170-amino acid insertion of unknown architecture and function in the metal- and DNA-binding TOPRIM domain of the GyrB subunit. We have determined the structure of the 212 kDa Escherichia coli gyrase DNA binding and cleavage core containing this insert to 3.1 Å resolution. We find that the insert adopts a novel, extended fold that braces the GyrB TOPRIM domain against the coiled-coil arms of its partner GyrA subunit. Structure-guided deletion of the insert greatly reduces the DNA binding, supercoiling and DNA-stimulated ATPase activities of gyrase. Mutation of a single amino acid at the contact point between the insert and GyrA more modestly impairs supercoiling and ATP turnover, and does not affect DNA binding. Our data indicate that the insert has two functions, acting as a steric buttress to pre-configure the primary DNA-binding site, and serving as a relay that may help coordinate communication between different functional domains.
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影响因子：
5.7
作者：
Costenaro, Lionel;Grossmann, J. Gunter;Maxwell, Anthony
通讯作者：
Maxwell, Anthony
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
64.8
作者：
Dong, Ken C.;Berger, James M.
通讯作者：
Berger, James M.
影响因子：
14.9
作者：
Davis IW;Leaver-Fay A;Chen VB;Block JN;Kapral GJ;Wang X;Murray LW;Arendall WB 3rd;Snoeyink J;Richardson JS;Richardson DC
通讯作者：
Richardson DC
影响因子：
64.8
作者：
Berger, JM;Gamblin, SJ;Wang, JC
通讯作者：
Wang, JC