Stoichiometry of MutS and MutL at unrepaired mismatches in vivo suggests a mechanism of repair.
Stoichiometry of MutS and MutL at unrepaired mismatches in vivo suggests a mechanism of repair.
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DOI：
10.1093/nar/gkr1298
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发表时间：
2012-05
影响因子：
14.9
通讯作者：
Matic I
中科院分区：
文献类型：
--
作者：
Elez M;Radman M;Matic I
错配修复（MMR）是一种进化上保守的DNA修复系统，它可以纠正DNA复制过程中出现的碱基错配。MutS识别并结合碱基对错配，而MutL蛋白与MutS错配复合物相互作用，并在DNA上的远端链识别位点触发MutH核酸内切酶活性。DNA上这两个远端位点之间的通讯机制尚不清楚。我们使用功能性荧光MMR蛋白MutS和MutL，以研究在生长的大肠杆菌细胞中实时错配的荧光MMR蛋白复合物的形成。我们发现MutS和MutL蛋白共定位在未修复的错配上形成荧光灶。平均而言，MutL病灶的强度是MutS病灶在单个错配上共定位的2.7倍。由MutHE56A突变蛋白提供的DNA上的位阻，其在链辨别位点结合但不切割DNA，使MutL聚焦荧光降低3倍。这表明MutL沿着DNA从错配位点向链辨别位点沿着积累。我们的研究结果证实了假设MutL的积累保证了错配和链歧视位点之间的MMR活动的协调。
Mismatch repair (MMR) is an evolutionarily conserved DNA repair system, which corrects mismatched bases arising during DNA replication. MutS recognizes and binds base pair mismatches, while the MutL protein interacts with MutS–mismatch complex and triggers MutH endonuclease activity at a distal-strand discrimination site on the DNA. The mechanism of communication between these two distal sites on the DNA is not known. We used functional fluorescent MMR proteins, MutS and MutL, in order to investigate the formation of the fluorescent MMR protein complexes on mismatches in real-time in growing Escherichia coli cells. We found that MutS and MutL proteins co-localize on unrepaired mismatches to form fluorescent foci. MutL foci were, on average, 2.7 times more intense than the MutS foci co-localized on individual mismatches. A steric block on the DNA provided by the MutHE56A mutant protein, which binds to but does not cut the DNA at the strand discrimination site, decreased MutL foci fluorescence 3-fold. This indicates that MutL accumulates from the mismatch site toward strand discrimination site along the DNA. Our results corroborate the hypothesis postulating that MutL accumulation assures the coordination of the MMR activities between the mismatch and the strand discrimination site.
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影响因子：
3.6
作者：
Fontaine F;Stewart EJ;Lindner AB;Taddei F
通讯作者：
Taddei F
影响因子：
16
作者：
Junop, MS;Obmolova, G;Yang, W
通讯作者：
Yang, W
DOI：
10.1073/pnas.0610149104
发表时间：
2007-05-22
影响因子：
11.1
作者：
Elez, Marina;Radman, Miroslav;Matic, Ivan
通讯作者：
Matic, Ivan
影响因子：
3.8
作者：
Junop, MS;Yang, W;Miller, JH
通讯作者：
Miller, JH
影响因子：
3.2
作者：
Macintyre, G;Doiron, KMJ;Cupples, CG
通讯作者：
Cupples, CG