The Escherichia coli MutL protein stimulates binding of Vsr and MutS to heteroduplex DNA
The Escherichia coli MutL protein stimulates binding of Vsr and MutS to heteroduplex DNA
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DOI：
10.1093/nar/26.4.948
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发表时间：
1998-02-15
影响因子：
14.9
通讯作者：
Marinus, MG
中科院分区：
文献类型：
--
作者：
Drotschmann, K;Aronshtam, A;Marinus, MG
VsrDNA错配核酸内切酶是非常短的补丁（VSP）DNA错配修复的关键酶，并以序列依赖的方式在T-G错配位点切割含T链。MutS是mutHLS修复系统的一部分，并与DNA中的不同错配结合。mutL基因产物的功能目前尚不清楚，但该基因的突变消除了mutHLS依赖性修复。MutL的缺失严重降低了VSP修复，但并没有消除它。纯化的MutL似乎起催化作用，将Vsr结合到其底物上;百分之一当量的MutL就足以带来显著的效果。MutL增强MutS与其底物的结合6倍，但以化学计量方式进行。突变研究表明MutL相互作用区域位于N-末端330个氨基酸内，MutL多聚化区域位于C-末端。MutL突变体单体形式可以刺激MutS结合。
Vsr DNA mismatch endonuclease is the key enzyme of very short patch (VSP) DNA mismatch repair and nicks the T-containing strand at the site of a T-G mismatch in a sequence-dependent manner. MutS is part of the mutHLS repair system and binds to diverse mismatches in DNA. The function of the mutL gene product is currently unclear but mutations in the gene abolish mutHLS-dependent repair. The absence of MutL severely reduces VSP repair but does not abolish it. purified MutL appears to act catalytically to bind Vsr to its substrate; one-hundredth of an equivalent of MutL is sufficient to bring about a significant effect. MutL enhances binding of MutS to its substrate 6-fold but does so in a stoichiometric manner. Mutational studies indicate that the MutL interaction region lies within the N-terminal 330 amino acids and that the MutL multimerization region is at the C-terminal end. MutL mutant monomeric forms can stimulate MutS binding.