Structural asymmetry in the Thermus thermophilus RuvC dimer suggests a basis for sequential strand cleavages during Holliday junction resolution.
Structural asymmetry in the Thermus thermophilus RuvC dimer suggests a basis for sequential strand cleavages during Holliday junction resolution.
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DOI：
10.1093/nar/gks1015
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发表时间：
2013-01-07
影响因子：
14.9
通讯作者：
Aihara H
中科院分区：
文献类型：
--
作者：
Chen L;Shi K;Yin Z;Aihara H
霍利迪连接（HJ）解离酶是结构特异性核酸内切酶，其切割在DNA重组和修复期间产生的四向DNA连接（HJ）。细菌RuvC是一种典型的HJ解离酶，其功能为同源二聚体，并精确地跨越连接点切割DNA链。为了深入了解RuvC对称链切割的潜在机制，我们对来自嗜热栖热菌（Thermus thermophilus）（T.th. RuvC）。T.th.的晶体结构。RuvC显示出与大肠杆菌RuvC相似的总体蛋白质折叠，但T. RuvC具有更紧密结合的二聚体界面，这可能反映了其热稳定性。HJ-DNA底物的结合模式可以从T. th. RuvC二聚体和HJ-DNA，以及硫酸根离子结合在蛋白质表面上的位置。出乎意料的是，T. th.在1.28 μ m分辨率下精制的RuvC同型二聚体在二聚体界面附近显示出明显的不对称性，在该区域具有催化重要的芳族残基。观察表明，T。RuvC同源二聚体在两种不对称构象之间相互转化，其中交替的亚基开启用于DNA链切割。该模型提供了一个结构基础的“缺口计数器缺口”机制在HJ决议，模式的HJ加工共享的原核和真核HJ分解酶。
Holliday junction (HJ) resolvases are structure-specific endonucleases that cleave four-way DNA junctions (HJs) generated during DNA recombination and repair. Bacterial RuvC, a prototypical HJ resolvase, functions as homodimer and nicks DNA strands precisely across the junction point. To gain insights into the mechanisms underlying symmetrical strand cleavages by RuvC, we performed crystallographic and biochemical analyses of RuvC from Thermus thermophilus (T.th. RuvC). The crystal structure of T.th. RuvC shows an overall protein fold similar to that of Escherichia coli RuvC, but T.th. RuvC has a more tightly associated dimer interface possibly reflecting its thermostability. The binding mode of a HJ-DNA substrate can be inferred from the shape/charge complementarity between the T.th. RuvC dimer and HJ-DNA, as well as positions of sulfate ions bound on the protein surface. Unexpectedly, the structure of T.th. RuvC homodimer refined at 1.28 Å resolution shows distinct asymmetry near the dimer interface, in the region harboring catalytically important aromatic residues. The observation suggests that the T.th. RuvC homodimer interconverts between two asymmetric conformations, with alternating subunits switched on for DNA strand cleavage. This model provides a structural basis for the ‘nick-counter-nick’ mechanism in HJ resolution, a mode of HJ processing shared by prokaryotic and eukaryotic HJ resolvases.
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影响因子：
11.4
作者：
IWASAKI, H;TAKAHAGI, M;SHINAGAWA, H
通讯作者：
SHINAGAWA, H
DOI：
10.1073/pnas.92.12.5635
发表时间：
1995-06-06
影响因子：
11.1
作者：
BENNETT, RJ;WEST, SC
通讯作者：
WEST, SC
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：
10.5
作者：
IWASAKI, H;TAKAHAGI, M;SHINAGAWA, H
通讯作者：
SHINAGAWA, H
DOI：
10.1107/s0907444909052925
发表时间：
2010-02
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Adams PD;Afonine PV;Bunkóczi G;Chen VB;Davis IW;Echols N;Headd JJ;Hung LW;Kapral GJ;Grosse-Kunstleve RW;McCoy AJ;Moriarty NW;Oeffner R;Read RJ;Richardson DC;Richardson JS;Terwilliger TC;Zwart PH
通讯作者：
Zwart PH