Interaction of potassium cyanide with the [Ni-4Fe-5S] active site cluster of CO dehydrogenase from Carboxydothermus hydrogenoformans
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Interaction of potassium cyanide with the [Ni-4Fe-5S] active site cluster of CO dehydrogenase from Carboxydothermus hydrogenoformans. / Ha, Seung-Wook; Korbas, Malgorzata; Klepsch, Mirjam; Meyer-Klaucke, Wolfram; Meyer, Ortwin; Svetlitchnyi, Vitali.
in: J BIOL CHEM, Jahrgang 282, Nr. 14, 06.04.2007, S. 10639-46.Publikationen: SCORING: Beitrag in Fachzeitschrift/Zeitung › SCORING: Zeitschriftenaufsatz › Forschung › Begutachtung
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TY - JOUR
T1 - Interaction of potassium cyanide with the [Ni-4Fe-5S] active site cluster of CO dehydrogenase from Carboxydothermus hydrogenoformans
AU - Ha, Seung-Wook
AU - Korbas, Malgorzata
AU - Klepsch, Mirjam
AU - Meyer-Klaucke, Wolfram
AU - Meyer, Ortwin
AU - Svetlitchnyi, Vitali
PY - 2007/4/6
Y1 - 2007/4/6
N2 - The Ni-Fe carbon monoxide (CO) dehydrogenase II (CODHII(Ch)) from the anaerobic CO-utilizing hydrogenogenic bacterium Carboxydothermus hydrogenoformans catalyzes the oxidation of CO, presumably at the Ni-(micro(2)S)-Fe1 subsite of the [Ni-4S-5S] cluster in the active site. The CO oxidation mechanism proposed on the basis of several CODHII(Ch) crystal structures involved the apical binding of CO at the nickel ion and the activation of water at the Fe1 ion of the cluster. To understand how CO interacts with the active site, we have studied the reactivity of the cluster with potassium cyanide and analyzed the resulting type of nickel coordination by x-ray absorption spectroscopy. Cyanide acts as a competitive inhibitor of reduced CODHII(Ch) with respect to the substrate CO and is therefore expected to mimic the substrate. It inhibits the enzyme reversibly, forming a nickel cyanide. In this reaction, one of the four square-planar sulfur ligands of nickel is replaced by the carbon atom of cyanide, suggesting removal of the micro(2)S from the Ni-(micro(2)S)-Fe1 subsite. Upon reactivation of the inhibited enzyme, cyanide is released, and the square-planar coordination of nickel by 4S ligands is recovered, which includes the reformation of the Ni-(micro(2)S)-Fe1 bridge. The results are summarized in a model of the CO oxidation mechanism at the [Ni-4Fe-5S] active site cluster of CODHII(Ch) from C. hydrogenoformans.
AB - The Ni-Fe carbon monoxide (CO) dehydrogenase II (CODHII(Ch)) from the anaerobic CO-utilizing hydrogenogenic bacterium Carboxydothermus hydrogenoformans catalyzes the oxidation of CO, presumably at the Ni-(micro(2)S)-Fe1 subsite of the [Ni-4S-5S] cluster in the active site. The CO oxidation mechanism proposed on the basis of several CODHII(Ch) crystal structures involved the apical binding of CO at the nickel ion and the activation of water at the Fe1 ion of the cluster. To understand how CO interacts with the active site, we have studied the reactivity of the cluster with potassium cyanide and analyzed the resulting type of nickel coordination by x-ray absorption spectroscopy. Cyanide acts as a competitive inhibitor of reduced CODHII(Ch) with respect to the substrate CO and is therefore expected to mimic the substrate. It inhibits the enzyme reversibly, forming a nickel cyanide. In this reaction, one of the four square-planar sulfur ligands of nickel is replaced by the carbon atom of cyanide, suggesting removal of the micro(2)S from the Ni-(micro(2)S)-Fe1 subsite. Upon reactivation of the inhibited enzyme, cyanide is released, and the square-planar coordination of nickel by 4S ligands is recovered, which includes the reformation of the Ni-(micro(2)S)-Fe1 bridge. The results are summarized in a model of the CO oxidation mechanism at the [Ni-4Fe-5S] active site cluster of CODHII(Ch) from C. hydrogenoformans.
KW - Absorptiometry, Photon
KW - Aldehyde Oxidoreductases
KW - Bacterial Proteins
KW - Binding Sites
KW - Carbon Monoxide
KW - Clostridium
KW - Iron
KW - Multienzyme Complexes
KW - Nickel
KW - Oxidation-Reduction
KW - Potassium Cyanide
KW - Sulfur
KW - Journal Article
KW - Research Support, Non-U.S. Gov't
U2 - 10.1074/jbc.M610641200
DO - 10.1074/jbc.M610641200
M3 - SCORING: Journal article
C2 - 17277357
VL - 282
SP - 10639
EP - 10646
JO - J BIOL CHEM
JF - J BIOL CHEM
SN - 0021-9258
IS - 14
ER -