Direct involvement of the TEN domain at the active site of human telomerase
Direct involvement of the TEN domain at the active site of human telomerase
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DOI：
10.1093/nar/gkq1083
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发表时间：
2011-03-01
影响因子：
14.9
通讯作者：
Bryan, Tracy M.
中科院分区：
文献类型：
--
作者：
Jurczyluk, Julie;Nouwens, Amanda S.;Bryan, Tracy M.
端粒酶是一种将DNA添加到染色体末端的核糖核蛋白。端粒酶催化蛋白亚基（TERT）含有一个N端结构域（TEN），它对端粒酶活性和持续合成能力非常重要。在这里，我们描述了一个突变的TEN结构域的人端粒酶逆转录酶，在一个大大增加的引物K-d，支持的作用，TEN结构域的DNA亲和力。酶动力学参数的测量显示，该突变酶在dNTP聚合中也有缺陷，特别是在复制RNA模板的位置51时。催化缺陷不依赖于DNA引物5 '区结合相互作用的存在，并且不是易位率的缺陷。这些数据表明，TEN结构域参与了在核苷酸添加期间将引物的3 '末端定位在活性位点中所需的构象变化，该功能与TEN结构域在提供DNA结合亲和力中的作用不同。
Telomerase is a ribonucleoprotein that adds DNA to the ends of chromosomes. The catalytic protein subunit of telomerase (TERT) contains an N-terminal domain (TEN) that is important for activity and processivity. Here we describe a mutation in the TEN domain of human TERT that results in a greatly increased primer K-d, supporting a role for the TEN domain in DNA affinity. Measurement of enzyme kinetic parameters has revealed that this mutant enzyme is also defective in dNTP polymerization, particularly while copying position 51 of the RNA template. The catalytic defect is independent of the presence of binding interactions at the 5'-region of the DNA primer, and is not a defect in translocation rate. These data suggest that the TEN domain is involved in conformational changes required to position the 3'-end of the primer in the active site during nucleotide addition, a function which is distinct from the role of the TEN domain in providing DNA binding affinity.