The mechanism of Mo-/Cu-dependent CO dehydrogenase.
Density functional theory computations at the B3LYP/SDDp//B3LYP/Lanl2DZ level were performed on model complexes derived from [(Me(2)C(2)S(2))Mo(O)(2)-S-CuSMe](2-) or its oxo protonated form to gain insight into the reaction steps involved in substrate oxidation of a Mo-/Cu-dependent CO dehydrogenase. Only the bisoxo but not the hydroxo oxo complex was found to oxidize CO exothermically. A thiocarbamate complex structurally characterized as the reaction product of the enzyme with the inhibitor n-butylisonitrile corresponds to a thermodynamic well on the potential energy surface. For the formation of the analogous thiocarbonate complex from CO oxidation, however, we do not find a significant thermodynamic driving force. In the protein matrix of the enzyme this species should be further destabilized, as it requires the metal centers to move apart considerably from each other.
Hofmann
Matthias
M
Anorganisch-Chemisches Institut, Universität Heidelberg, 69120 Heidelberg, Germany. matthias.hofmann@aci.uni-heidelberg.de
Kassube
Jutta K
JK
Graf
Tobias
T
D000445:Aldehyde Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D020561:Alphaproteobacteria / Q000201:enzymology; D002384:Catalysis; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D004735:Energy Transfer; D008956:Models, Chemical; D015394:Molecular Structure; D008982:Molybdenum / Q000737:chemistry* / Q000378:metabolism; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000378:metabolism*
D009097:Multienzyme Complexes; D003300:Copper; D008982:Molybdenum; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase