Novel mutator mutants of E-coli nrdAB ribonucleotide reductase: Insight into allosteric regulation and control of mutation rates
Novel mutator mutants of E-coli nrdAB ribonucleotide reductase: Insight into allosteric regulation and control of mutation rates
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DOI：
10.1016/j.dnarep.2012.02.001
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发表时间：
2012-05-01
期刊：
影响因子：
3.8
通讯作者：
Schaaper, Roe M.
中科院分区：
文献类型：
--
作者：
Ahluwalia, Deepti;Bienstock, Rachelle J.;Schaaper, Roe M.
核糖核苷酸还原酶（RNR）是负责产生DNA合成的直接前体5 '-脱氧核苷三磷酸（dNTPs）的关键酶。严格控制dNTP水平以允许DNA合成的高效率和保真度。这种控制大部分发生在RNR的反馈过程的水平，但这些机制的详细了解仍然缺乏。在大肠杆菌中使用遗传方法，Ia类RNR的范例，我们分离出23种新的RNR突变体，其突变率沿着改变的dNTP水平而升高。RNR中负责的氨基酸取代位于三个不同的区域：（i）（d）ATP结合活性结构域，（ii）与活性结构域相邻的小亚基中的新区域，以及（iii）dNTP结合特异性位点，其中几个与不同的dNTP池改变和不同的突变结果相关。这些突变体提供了新的见解RNR的精确机制，RNR的调节和如何dNTP池的干扰导致RNR的缺陷可能会导致突变增加。由爱思唯尔公司出版
Ribonucleotide reductase (RNR) is the enzyme critically responsible for the production of the 5'-deoxynucleoside-triphosphates (dNTPs), the direct precursors for DNA synthesis. The dNTP levels are tightly controlled to permit high efficiency and fidelity of DNA synthesis. Much of this control occurs at the level of the RNR by feedback processes, but a detailed understanding of these mechanisms is still lacking. Using a genetic approach in the bacterium Escherichia coli, a paradigm for the class Ia RNRs, we isolated 23 novel RNR mutants displaying elevated mutation rates along with altered dNTP levels. The responsible amino-acid substitutions in RNR reside in three different regions: (i) the (d)ATP-binding activity domain, (ii) a novel region in the small subunit adjacent to the activity domain, and (iii) the dNTP-binding specificity site, several of which are associated with different dNTP pool alterations and different mutational outcomes. These mutants provide new insight into the precise mechanisms by which RNR is regulated and how dNTP pool disturbances resulting from defects in RNR can lead to increased mutation. Published by Elsevier B.V.