Abstract
Anaerobic CO dehydrogenases catalyze the reversible oxidation of CO to CO2 at a complex Ni-, Fe-, and S-containing metal center called cluster C. We report crystal structures of CO dehydrogenase II from Carboxydothermus hydrogenoformans in three different states. In a reduced state, exogenous CO2 supplied in solution is bound and reductively activated by cluster C. In the intermediate structure, CO2 acts as a bridging ligand between Ni and the asymmetrically coordinated Fe, where it completes the square-planar coordination of the Ni ion. It replaces a water/hydroxo ligand bound to the Fe ion in the other two states. The structures define the mechanism of CO oxidation and CO2 reduction at the Ni-Fe site of cluster C.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Aldehyde Oxidoreductases / chemistry
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Aldehyde Oxidoreductases / isolation & purification
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Aldehyde Oxidoreductases / metabolism*
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Anaerobiosis
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Binding Sites
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Carbon Dioxide / metabolism*
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Carbon Monoxide / metabolism
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Crystallization
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Crystallography, X-Ray
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Iron / chemistry
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Iron / metabolism
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Ligands
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Multienzyme Complexes / chemistry
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Multienzyme Complexes / isolation & purification
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Multienzyme Complexes / metabolism*
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Nickel / chemistry
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Nickel / metabolism
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Peptococcaceae / enzymology*
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Protein Conformation
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Recombinant Proteins / chemistry
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Recombinant Proteins / isolation & purification
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Recombinant Proteins / metabolism
Substances
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Ligands
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Multienzyme Complexes
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Recombinant Proteins
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Carbon Dioxide
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Nickel
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Carbon Monoxide
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Iron
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Aldehyde Oxidoreductases
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carbon monoxide dehydrogenase
Associated data
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PDB/3B51
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PDB/3B52
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PDB/3B53