Crystallographic snapshots of cyanide- and water-bound C-clusters from bifunctional carbon monoxide dehydrogenase/acetyl-CoA synthase.
Crystallographic snapshots of cyanide- and water-bound C-clusters from bifunctional carbon monoxide dehydrogenase/acetyl-CoA synthase.
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DOI：
10.1021/bi900574h
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发表时间：
2009-08-11
期刊：
影响因子：
2.9
通讯作者：
Drennan, Catherine L.
中科院分区：
文献类型：
--
作者：
Kung, Yan;Doukov, Tzanko I.;Seravalli, Javier;Ragsdale, Stephen W.;Drennan, Catherine L.
含镍一氧化碳脱氢酶（CODHs）催化一氧化碳氧化为二氧化碳，在全球碳循环中起着至关重要的作用。不寻常的催化CODH c -簇在晶体学上被表征为NiFe4S4或NiFe4S5金属中心，后者含有第五个，额外的硫化物，连接Ni和一个独特的Fe位点。为了确定这种桥接硫化物是否具有催化作用，并进一步探索c -簇的机制，我们获得了310 kDa双功能CODH/乙酰辅酶a合成酶复合物的晶体结构，这些复合物既与底物H2O/OH -分子结合，也与氰化物抑制剂结合。x射线衍射数据来自天然晶体和浸泡在含氰化钾溶液中的相同晶体。在这两种结构中，底物H2O/OH−分子都与c -簇中独特的Fe位点结合。我们还观察到氰化物以弯曲构象结合在c簇的Ni上，靠近底物H2O/OH−分子。重要的是，桥接硫化物在这两种结构中都不存在。由于这些形式的c -簇代表了反应发生前的配位环境，我们的研究结果不支持第五种桥接硫化物在酶机制中起催化作用。这里展示的晶体结构，以及最近从其他生物中获得的CODHs结构，使我们朝着c -簇氧化CO的统一机制方向发展，c -簇是一种环境重要酶的催化中心。
Nickel-containing carbon monoxide dehydrogenases (CODHs) reversibly catalyze the oxidation of carbon monoxide to carbon dioxide and are of vital importance in the global carbon cycle. The unusual catalytic CODH C-cluster has been crystallographically characterized as either a NiFe4S4 or a NiFe4S5 metal center, the latter containing a fifth, additional sulfide that bridges Ni and a unique Fe site. To determine whether this bridging sulfide is catalytically relevant and to further explore the mechanism of the C-cluster, we obtained crystal structures of the 310 kDa bifunctional CODH/acetyl-CoA synthase complex from Moorella thermoacetica bound both with a substrate H2O/OH− molecule and with a cyanide inhibitor. X-ray diffraction data were collected from native crystals and from identical crystals soaked in a solution containing potassium cyanide. In both structures, the substrate H2O/OH− molecule exhibits binding to the unique Fe site of the C-cluster. We also observe cyanide binding in a bent conformation to Ni of the C-cluster, adjacent the substrate H2O/OH− molecule. Importantly, the bridging sulfide is not present in either structure. As these forms of the C-cluster represent the coordination environment immediately before the reaction takes place, our findings do not support a fifth, bridging sulfide playing a catalytic role in the enzyme mechanism. The crystal structures presented here, along with recent structures of CODHs from other organisms, have led us toward a unified mechanism for CO oxidation by the C-cluster, the catalytic center of an environmentally important enzyme.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
15
作者：
DeRose, VJ;Telser, J;Hoffman, BM
通讯作者：
Hoffman, BM
影响因子：
2.9
作者：
ENSIGN, SA;BONAM, D;LUDDEN, PW
通讯作者：
LUDDEN, PW
影响因子：
2.9
作者：
ENSIGN, SA;HYMAN, MR;LUDDEN, PW
通讯作者：
LUDDEN, PW
DOI：
10.1107/s0907444998003254
发表时间：
1998-09-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
Brunger, AT;Adams, PD;Warren, GL
通讯作者：
Warren, GL