Catalytic mechanism of quinoprotein methanol dehydrogenase: A theoretical and x-ray crystallographic investigation.
The catalytic mechanism of the reductive half reaction of the quinoprotein methanol dehydrogenase (MDH) is believed to proceed either through a hemiketal intermediate or by direct transfer of a hydride ion from the substrate methyl group to the cofactor, pyrroloquinoline quinone (PQQ). A crystal structure of the enzyme-substrate complex of a similar quinoprotein, glucose dehydrogenase, has recently been reported that strongly favors the hydride transfer mechanism in that enzyme. A theoretical analysis and an improved refinement of the 1.9-A resolution crystal structure of MDH from Methylophilus methylotrophus W3A1 in the presence of methanol, reported earlier, indicates that the observed tetrahedral configuration of the C-5 atom of PQQ in that study represents the C-5-reduced form of the cofactor and lends support for a hydride transfer mechanism for MDH.
Zheng
Y J
YJ
DuPont Agriculture Products, Stine-Haskell Research Center, Newark, DE 19714, USA.
Xia Zx
Chen Zw
Mathews
F S
FS
Bruice
T C
TC
D000429:Alcohol Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D000432:Methanol / Q000378:metabolism; D008956:Models, Chemical; D010084:Oxidation-Reduction; D011485:Protein Binding; D011487:Protein Conformation; D011789:Quantum Theory; D013379:Substrate Specificity
D001426:Bacterial Proteins; D000429:Alcohol Oxidoreductases; C019641:alcohol dehydrogenase (acceptor); D000432:Methanol