质子耦合电子转移
脱卤酶
电子转移
脱质子化
催化作用
化学
光化学
脱氯作用
组合化学
立体化学
酶
有机化学
生物降解
离子
作者
Xuan Zhang,Zikuan Wang,Zhen Li,Sason Shaik,Binju Wang
标识
DOI:10.1021/acscatal.2c06306
摘要
Reductive dehalogenases (RDases) are key enzymes involved in the degradation of organohalide compounds. Despite extensive experimental and computational studies, the catalytic mechanism of RDases remains unclear. We show here that the proximal [4Fe–4S]1+ cluster of the reductive dehalogenase PceA can mediate a proton-coupled electron transfer (PCET) process to quench the substrate radical. Such a [4Fe–4S]1+-mediated PCET process is enhanced by both exchange and super-exchange interactions. The participation of [4Fe–4S]1+ in mediating a PCET process in RDases is unexpected, although well known in reducing Co(II). In addition, in RDases, the Arg305 residue acts as an efficient proton donor for the PCET reactions. The deprotonated Tyr246 serves to maintain the favorable conformation of Arg305 during catalysis and sustains its proton donation ability, which is requested during the PCET reaction. Such a novel mechanism enables the efficient detoxification of chloroalkene pollutants by the reductive dehalogenase PceA, which also rationalizes the selective dechlorination of trichloroethene to form cis-1,2-dichloroethylene. These results highlight the critical role of the proximal [4Fe–4S].
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