An incoming nucleotide imposes an anti to syn conformational change on the templating purine in the human DNA polymerase-ι active site
An incoming nucleotide imposes an anti to syn conformational change on the templating purine in the human DNA polymerase-ι active site
复制标题
DOI：
10.1016/j.str.2006.01.010
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发表时间：
2006-04-01
期刊：
影响因子：
5.7
通讯作者：
Aggarwal, AK
中科院分区：
文献类型：
--
作者：
Nair, DT;Johnson, RE;Aggarwal, AK
底物诱导的蛋白质构象变化是酶促反应的关键。复制性DNA聚合酶，例如，从一个开放的构象转化为一个封闭的响应dNTP结合。人类DNA聚合酶iota （hPol iota）是Y家族DNA聚合酶的一员，与其他聚合酶相比，它对相反模板嘌呤核苷酸结合的熟练度和保真度要高得多。我们在这里提出了一个hPol - iota二元配合物的晶体学分析，它与三元配合物一起表明，与复制DNA聚合酶相反，DNA，而不是聚合酶，经历了初级底物诱导的构象变化。传入的dNTP将模板A和G从反分子“推”到由刚性hPol - iota活性位点决定的同步构象。总之，这些结构确定了模板选择的机制，其中dNTP结合诱导了模板嘌呤的构象转换，从而产生Hoogsteen碱基配对。
Substrate-induced conformational change of the protein is the linchpin of enzymatic reactions. Replicative DNA polymerases, for example, convert from an open to a closed conformation in response to dNTP binding. Human DNA polymerase-iota (hPol iota), a member of the Y family of DNA polymerases, differs strikingly from other polymerases in its much higher proficiency and fidelity for nucleotide incorporation opposite template purines than opposite template pyrimidines. We present here a crystallographic analysis of hPol iota binary complexes, which together with the ternary complexes show that, contrary to replicative DNA polymerases, the DNA, and not the polymerase, undergoes the primary substrate-induced conformational change. The incoming dNTP "pushes" templates A and G from the anti to the syn conformation dictated by a rigid hPol iota active site. Together, the structures posita mechanism for template selection wherein dNTP binding induces a conformational switch in template purines for productive Hoogsteen base pairing.