FAD binding, cobinamide binding and active site communication in the corrin reductase (CobR).
FAD binding, cobinamide binding and active site communication in the corrin reductase (CobR).
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FAD结合，Corin还原酶（COBR）中的核酰胺结合和主动位点通信。
DOI：
10.1042/bsr20140060
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发表时间：
2014-07-04
影响因子：
4
通讯作者：
Warren MJ
中科院分区：
文献类型：
--
作者：
Lawrence AD;Taylor SL;Scott A;Rowe ML;Johnson CM;Rigby SE;Geeves MA;Pickersgill RW;Howard MJ;Warren MJ
腺苷钴胺素是维生素B12的辅酶形式，是自然界中最复杂的辅酶之一，其从头生物合成沿着厌氧或有氧代谢途径进行。需氧合成涉及在腺苷酸化可以发生之前将咕啉环的中心螯合的钴金属离子从Co（II）还原为Co（I）。咕啉还原酶（CobR）已被确定为催化金属离子还原的可能试剂。在此，我们揭示了羊种布鲁氏菌CobR如何结合其辅酶FAD（黄素二核苷酸），我们还表明，该酶可以结合咕啉底物，这与其在咕啉环的钴还原中的作用一致。停流动力学和EPR揭示了CobR二聚体中的机械不对称性，该机械不对称性提供了由NADH的两个电子还原到Co（II）到Co（I）的单电子还原之间的潜在联系。CobR是参与腺苷钴胺素生物合成的咕啉还原酶。使用一系列的生物物理技术，我们已经获得了底物结合的分子细节和研究蛋白质的稳定性。动力学实验已经确定了半位点反应性。
Adenosylcobalamin, the coenzyme form of vitamin B12, is one Nature's most complex coenzyme whose de novo biogenesis proceeds along either an anaerobic or aerobic metabolic pathway. The aerobic synthesis involves reduction of the centrally chelated cobalt metal ion of the corrin ring from Co(II) to Co(I) before adenosylation can take place. A corrin reductase (CobR) enzyme has been identified as the likely agent to catalyse this reduction of the metal ion. Herein, we reveal how Brucella melitensis CobR binds its coenzyme FAD (flavin dinucleotide) and we also show that the enzyme can bind a corrin substrate consistent with its role in reduction of the cobalt of the corrin ring. Stopped-flow kinetics and EPR reveal a mechanistic asymmetry in CobR dimer that provides a potential link between the two electron reduction by NADH to the single electron reduction of Co(II) to Co(I). CobR is a corrin reductase involved in the biosynthesis of adenosylcobalamin. Using a range of biophysical techniques, we have obtained molecular details on substrate binding and investigated protein stability. Kinetic experiments have identified half-site reactivity.