Coenzyme B induced coordination of coenzyme M via its thiol group to Ni(I) of F430 in active methyl-coenzyme M reductase.
Methyl-coenzyme M reductase (MCR) catalyzes the reaction of methyl-coenzyme M (CH3-S-CoM) with coenzyme B (HS-CoB) to methane and CoM-S-S-CoB. At the active site, it contains the nickel porphinoid F430, which has to be in the Ni(I) oxidation state for the enzyme to be active. How the substrates interact with the active site Ni(I) has remained elusive. We report here that coenzyme M (HS-CoM), which is a reversible competitive inhibitor to methyl-coenzyme M, interacts with its thiol group with the Ni(I) and that for interaction the simultaneous presence of coenzyme B is required. The evidence is based on X-band continuous wave EPR and Q-band hyperfine sublevel correlation spectroscopy of MCR in the red2 state induced with 33S-labeled coenzyme M and unlabeled coenzyme B.
Finazzo
Cinzia
C
Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland.
Harmer
Jeffrey
J
Bauer
Carsten
C
Jaun
Bernhard
B
Duin
Evert C
EC
Mahlert
Felix
F
Goenrich
Meike
M
Thauer
Rudolf K
RK
Van Doorslaer
Sabine
S
Schweiger
Arthur
A
D004578:Electron Spin Resonance Spectroscopy; D015080:Mesna / Q000737:chemistry* / Q000378:metabolism; D008665:Metalloporphyrins / Q000737:chemistry* / Q000378:metabolism; D009532:Nickel / Q000737:chemistry* / Q000378:metabolism; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D010769:Phosphothreonine / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry* / Q000378:metabolism
D008665:Metalloporphyrins; D013438:Sulfhydryl Compounds; C049349:7-mercaptoheptanoylthreonine phosphate; D010769:Phosphothreonine; C023540:factor F430; D009532:Nickel; D010088:Oxidoreductases; C021572:methyl coenzyme M reductase; D015080:Mesna