Structure of the α2ε2 Ni-dependent CO dehydrogenase component of the Methanosarcina barkeri acetyl-CoA decarbonylase/synthase complex
Structure of the α2ε2 Ni-dependent CO dehydrogenase component of the Methanosarcina barkeri acetyl-CoA decarbonylase/synthase complex
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DOI：
10.1073/pnas.0800415105
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发表时间：
2008-07-15
影响因子：
11.1
通讯作者：
Chan, Michael K.
中科院分区：
文献类型：
--
作者：
Gong, Weimin;Hao, Bing;Chan, Michael K.
Ni 依赖性一氧化碳脱氢酶 (Ni-CODH) 是一个多样化的酶家族，可催化产乙酸菌、产甲烷菌和一些 CO 使用细菌中的可逆 CO:CO2 氧化还原酶活性。来自使用 CO 的细菌和产乙酸菌的 Ni-CODH 的晶体学揭示了 Ni-CODH 核心的整体折叠，并提出了介导 CO:CO2 相互转化的 C 簇的结构。尽管取得了这些进展，一氧化碳氧化的机制仍然难以捉摸。在此，我们报告了来自产甲烷古菌的一类独特的 Ni-CODH 的结构：来自 α(8)beta(8)gamma(8)delta(8)epsilon(8) CODH/乙酰辅酶A脱羰酶/合酶复合物的 alpha(2)epsilon(2) 组分，该复合物是地球上大部分生物甲烷产生的酶。这种 Ni-CODH 组分的结构为迄今为止未观察到的状态提供了支持，其中 CO 和 H2O/OH- 分别与 C 簇的 Ni 和外源 FCII 铁结合，并提供了对非产甲烷 Ni-CODH 中不存在的 F 亚基和 FeS 结构域的结构和功能作用的深入了解。
Ni-dependent carbon monoxide dehydrogenases (Ni-CODHs) are a diverse family of enzymes that catalyze reversible CO:CO2 oxidoreductase activity in acetogens, methanogens, and some CO-using bacteria. Crystallography of Ni-CODHs from CO-using bacteria and acetogens has revealed the overall fold of the Ni-CODH core and has suggested structures for the C cluster that mediates CO:CO2 interconversion. Despite these advances, the mechanism of CO oxidation has remained elusive. Herein, we report the structure of a distinct class of Ni-CODH from methanogenic archaea: the alpha(2)epsilon(2) component from the alpha(8)beta(8)gamma(8)delta(8)epsilon(8) CODH/acetyl-CoA decarbonylase/synthase complex, an enzyme responsible for the majority of biogenic methane production on Earth. The structure of this Ni-CODH component provides support for a hitherto unobserved state in which both CO and H2O/OH- bind to the Ni and the exogenous FCII iron of the C cluster, respectively, and offers insight into the structures and functional roles of the F-subunit and FeS domain not present in nonmethanogenic Ni-CODHs.