核苷酸还原酶
变构调节
核苷酸
效应器
脱氧核糖核酸
嘌呤代谢
生物
生物化学
活动站点
大肠杆菌
化学
DNA
DNA复制
嘌呤
结合位点
酶
核苷酸
立体化学
基因
蛋白质亚单位
作者
Christina M. Zimanyi,Percival Yang-Ting Chen,Gyunghoon Kang,Michael A. Funk,Catherine L. Drennan
出处
期刊:eLife
[eLife Sciences Publications, Ltd.]
日期:2016-01-12
卷期号:5
被引量:59
摘要
Ribonucleotide reductase (RNR) converts ribonucleotides to deoxyribonucleotides, a reaction that is essential for DNA biosynthesis and repair. This enzyme is responsible for reducing all four ribonucleotide substrates, with specificity regulated by the binding of an effector to a distal allosteric site. In all characterized RNRs, the binding of effector dATP alters the active site to select for pyrimidines over purines, whereas effectors dGTP and TTP select for substrates ADP and GDP, respectively. Here, we have determined structures of Escherichia coli class Ia RNR with all four substrate/specificity effector-pairs bound (CDP/dATP, UDP/dATP, ADP/dGTP, GDP/TTP) that reveal the conformational rearrangements responsible for this remarkable allostery. These structures delineate how RNR 'reads' the base of each effector and communicates substrate preference to the active site by forming differential hydrogen bonds, thereby maintaining the proper balance of deoxynucleotides in the cell.
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