Structural insights into DNA polymerase β deterrents for misincorporation support an induced-fit mechanism for fidelity
Structural insights into DNA polymerase β deterrents for misincorporation support an induced-fit mechanism for fidelity
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DOI：
10.1016/j.str.2004.08.001
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发表时间：
2004-10-01
期刊：
影响因子：
5.7
通讯作者：
Wilson, SH
中科院分区：
文献类型：
--
作者：
Krahn, JM;Beard, WA;Wilson, SH
DNA聚合酶通常从结构相似的分子库中选择正确的核苷酸，以保持沃森-克里克碱基配对规则。我们报告的DNA聚合酶β的结构与DNA错配位于聚合酶的活性位点。这通过使用将错配（模板-引物，A-C或T-C）捕获在新生碱基对结合口袋中的带切口的产物DNA来实现。每个错配复合物的结构表明碱基彼此不形成氢键，而是形成错配碱基部分重叠的交错排列。这防止了被认为是催化循环所需的N亚结构域的闭合/打开。N亚结构域的部分开放构象导致不同的氢键网络，其对于每个错配是独特的。这些结构定义了与底物特异性的诱导拟合模型一致的错误插入的不同分子方面。
DNA polymerases generally select the correct nucleotide from a pool of structurally similar molecules to preserve Watson-Crick base-pairing rules. We report the structure of DNA polymerase beta with DNA mismatches situated in the polymerase active site. This was achieved by using nicked product DNA that traps the mispair (template-primer, A-C or T-C) in the nascent base pair binding pocket. The structure of each mispair complex indicates that the bases do not form hydrogen bonds with one another, but form a staggered arrangement where the bases of the mispair partially overlap. This prevents closure/opening of the N subdomain that is believed to be required for catalytic cycling. The partially open conformation of the N subdomain results in distinct hydrogen bonding networks that are unique for each mispair. These structures define diverse molecular aspects of misinsertion that are consistent with the induced-fit model for substrate specificity.