Proofreading exonuclease on a tether: the complex between the E. coli DNA polymerase III subunits α, epsilon, θ and β reveals a highly flexible arrangement of the proofreading domain.
Proofreading exonuclease on a tether: the complex between the E. coli DNA polymerase III subunits α, epsilon, θ and β reveals a highly flexible arrangement of the proofreading domain.
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DOI：
10.1093/nar/gkt162
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发表时间：
2013-05-01
影响因子：
14.9
通讯作者：
Dixon NE
中科院分区：
文献类型：
--
作者：
Ozawa K;Horan NP;Robinson A;Yagi H;Hill FR;Jergic S;Xu ZQ;Loscha KV;Li N;Tehei M;Oakley AJ;Otting G;Huber T;Dixon NE
三个(αεθ)核心亚单位和β2滑动夹的复合体负责大肠杆菌染色体DNA复制酶POLIII的DNA合成。α(聚合酶)的PHP域和ε(校对核酸外切酶)亚单位的C末端片段之间的复合体的1.7o晶体结构表明，ε在远离聚合酶活性部位的位置与α结合。α和ε都含有钳制结合基序(CBM)，通过POL III以聚合模式与β2同时相互作用。这两种CBM的增强使分离到稳定的αεθ:β2复合体。重组αεθ:β2的核磁共振实验表明，连接ε核酸外切酶结构域及其α结合片段的连接子中有22个残基的高迁移率。尽管如此，小角X射线散射数据表明，增强的CBMS孤立的络合物具有致密的结构，但仍然是柔性的。在α-PHP域的不同位置与对苯甲酰基-L-苯丙氨酸进行光交联证实了系链的构象可变性。带有引物-模板αεθ:β的DNA2复制酶复合体的结构模型结合了所有可用的结构数据。
A complex of the three (αεθ) core subunits and the β2 sliding clamp is responsible for DNA synthesis by Pol III, the Escherichia coli chromosomal DNA replicase. The 1.7 Å crystal structure of a complex between the PHP domain of α (polymerase) and the C-terminal segment of ε (proofreading exonuclease) subunits shows that ε is attached to α at a site far from the polymerase active site. Both α and ε contain clamp-binding motifs (CBMs) that interact simultaneously with β2 in the polymerization mode of DNA replication by Pol III. Strengthening of both CBMs enables isolation of stable αεθ:β2 complexes. Nuclear magnetic resonance experiments with reconstituted αεθ:β2 demonstrate retention of high mobility of a segment of 22 residues in the linker that connects the exonuclease domain of ε with its α-binding segment. In spite of this, small-angle X-ray scattering data show that the isolated complex with strengthened CBMs has a compact, but still flexible, structure. Photo-crosslinking with p-benzoyl-L-phenylalanine incorporated at different sites in the α-PHP domain confirm the conformational variability of the tether. Structural models of the αεθ:β2 replicase complex with primer-template DNA combine all available structural data.
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影响因子：
64.5
作者：
Franklin, MC;Wang, JM;Steitz, TA
通讯作者：
Steitz, TA
影响因子：
64.5
作者：
Bailey, Scott;Wing, Richard A.;Steitz, Thomas A.
通讯作者：
Steitz, Thomas A.
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：
64.5
作者：
Jeruzalmi, D;Yurieva, O;Kuriyan, J
通讯作者：
Kuriyan, J
影响因子：
64.5
作者：
KONG, XP;ONRUST, R;KURIYAN, J
通讯作者：
KURIYAN, J