Structural basis for organohalide respiration
Structural basis for organohalide respiration
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DOI：
10.1126/science.1258118
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发表时间：
2014-10-24
期刊：
影响因子：
56.9
通讯作者：
Dobbek, Holger
中科院分区：
文献类型：
--
作者：
Bommer, Martin;Kunze, Cindy;Dobbek, Holger
呼吸有机卤化物的微生物可以利用各种持久性污染物，包括三氯乙烯（TCE），作为终端电子受体。有机卤化物呼吸作用的最后两个电子转移步骤是由还原性脱卤酶催化的。在这里，我们报告的X-射线晶体结构的PceA，一个原型的脱卤酶从Sulfuroacellum multivorans，以及结构的PceA在复杂的TCE和产品类似物。活性位点在硝基还原酶折叠内含有一个深埋的norpseudo-B-12辅因子，也在哺乳动物B-12分子伴侣中发现。PceA的结构揭示了钴胺素如何支持利用由高度可变的底物捕获区封端的保守的B-12结合支架的还原性卤消除。
Organohalide-respiring microorganisms can use a variety of persistent pollutants, including trichloroethene (TCE), as terminal electron acceptors. The final two-electron transfer step in organohalide respiration is catalyzed by reductive dehalogenases. Here we report the x-ray crystal structure of PceA, an archetypal dehalogenase from Sulfurospirillum multivorans, as well as structures of PceA in complex with TCE and product analogs. The active site harbors a deeply buried norpseudo-B-12 cofactor within a nitroreductase fold, also found in a mammalian B-12 chaperone. The structures of PceA reveal how a cobalamin supports a reductive haloelimination exploiting a conserved B-12-binding scaffold capped by a highly variable substrate-capturing region.