Carbon dioxide activation at the Ni,Fe-cluster of anaerobic carbon monoxide dehydrogenase.
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.
Laboratorium Proteinkristallographie and Forschungszentrum für Bio-Makromoleküle, Universität Bayreuth, D-95440 Bayreuth, Germany.
Jae-Hun
JH
Jeoung
Holger
H
Dobbek
D000445:Aldehyde Oxidoreductases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000693:Anaerobiosis; D001665:Binding Sites; D002245:Carbon Dioxide / Q000378:metabolism*; D002248:Carbon Monoxide / Q000378:metabolism; D003460:Crystallization; D018360:Crystallography, X-Ray; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D008024:Ligands; D009097:Multienzyme Complexes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D009532:Nickel / Q000737:chemistry / Q000378:metabolism; D010459:Peptococcaceae / Q000201:enzymology*; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
D008024:Ligands; D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D002245:Carbon Dioxide; D009532:Nickel; D002248:Carbon Monoxide; D007501:Iron; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase