Stepwise mechanism for transcription fidelity.
Stepwise mechanism for transcription fidelity.
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DOI：
10.1186/1741-7007-8-54
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发表时间：
2010-05-07
期刊：
影响因子：
5.4
通讯作者：
Zenkin N
中科院分区：
文献类型：
--
作者：
Yuzenkova Y;Bochkareva A;Tadigotla VR;Roghanian M;Zorov S;Severinov K;Zenkin N
转录是基因表达的第一步，其特征在于RNA合成的高保真度。在转录过程中，RNA聚合酶活性中心不仅区分非互补的核糖NTP底物，而且还区分互补的2 '-和3'-脱氧NTP。一个灵活的结构域的RNA聚合酶活性中心，触发环，已被证明在这一过程中发挥重要作用，但这种参与的机制仍然难以捉摸。在这里，我们表明，转录保真度是通过一个多步骤的过程。活性中心的初始结合是一些非互补底物的主要鉴别步骤，尽管对于其余的错误掺入事件，在该步骤的鉴别非常差。在第二步中，基于反应过渡态稳定性的差异和部分地基于一般碱催化的差异，区分非互补和2 '-脱氧NTP，用于正确底物与非正确底物。该步骤由触发环中参与催化的两个残基决定。在接下来的步骤中，通过触发环的重排从活性中心主动去除非互补和2 '-脱氧NTP。区别于上述底物的唯一步骤是基于在不存在3 'OH的情况下未能定向触发环催化残基。我们证明了多亚基RNA聚合酶的转录保真度是通过一个逐步的过程实现的。我们表明，个别步骤有助于不同的歧视对各种错误的基板。我们定义的机制和贡献，这些步骤中的每一个转录的整体保真度。
Transcription is the first step of gene expression and is characterized by a high fidelity of RNA synthesis. During transcription, the RNA polymerase active centre discriminates against not just non-complementary ribo NTP substrates but also against complementary 2'- and 3'-deoxy NTPs. A flexible domain of the RNA polymerase active centre, the Trigger Loop, was shown to play an important role in this process, but the mechanisms of this participation remained elusive. Here we show that transcription fidelity is achieved through a multi-step process. The initial binding in the active centre is the major discrimination step for some non-complementary substrates, although for the rest of misincorporation events discrimination at this step is very poor. During the second step, non-complementary and 2'-deoxy NTPs are discriminated against based on differences in reaction transition state stabilization and partly in general base catalysis, for correct versus non-correct substrates. This step is determined by two residues of the Trigger Loop that participate in catalysis. In the following step, non-complementary and 2'-deoxy NTPs are actively removed from the active centre through a rearrangement of the Trigger Loop. The only step of discrimination against 3'-deoxy substrates, distinct from the ones above, is based on failure to orient the Trigger Loop catalytic residues in the absence of 3'OH. We demonstrate that fidelity of transcription by multi-subunit RNA polymerases is achieved through a stepwise process. We show that individual steps contribute differently to discrimination against various erroneous substrates. We define the mechanisms and contributions of each of these steps to the overall fidelity of transcription.
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影响因子：
16.8
作者：
通讯作者：
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影响因子：
16
作者：
Kireeva, Maria L.;Nedialkov, Yuri A.;Kashlev, Mikhail
通讯作者：
Kashlev, Mikhail
影响因子：
14.3
作者：
Runarsson, TP;Yao, X
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Yao, X
影响因子：
16
作者：
Kettenberger, H;Armache, KJ;Cramer, P
通讯作者：
Cramer, P
DOI：
10.1073/pnas.0905402106
发表时间：
2009-11-10
影响因子：
11.1
作者：
Miropolskaya, Nataliya;Artsimovitch, Irina;Kulbachinskiy, Andrey
通讯作者：
Kulbachinskiy, Andrey