ATP synthesis coupled to electron transfer from H2 to the heterodisulfide of 2‐mercaptoethanesulfonate and 7‐mercaptoheptanoylthreonine phosphate in vesicle preparations of the methanogenic bacterium strain Gö1

[摘要]

Crude vesicle preparations of the methanogenic strain Gol were able to couple the reduction of the heterodisulfide of 2-mercaptoethanesulfonate and 7-mercaptoheptanoylthreonine phosphate (CoM-S-S-HTP) by H₂ with ATP formation. The rate of ATP synthesis was 1 mg protein. ATP synthesis and disulfide reduction were only observed with CoM-S-S-HTP, but not with CoM-S-S-CoM or HTP-S-S-HTP. The methylreductase inhibitor 2-bromoethanesulfonic acid had no effect on ATP synthesis induced by CoM-S-S-HTP reduction with H₂. ATP synthesis was completely inhibited by the uncoupler SF 6847 whereas the concomitant CoM-S-S-HTP reduction was stimulated. The ATP synthase inhibitors DCCD and DES also inhibited ATP formation completely and decreased the CoM-S-S-HTP reduction rate to 35% of the control. These inhibitory effects were abolished by addition of the uncoupler. From these results it is concluded that energy coupling between the electron transfer from H₂ to the heterodisulfide and ATP synthesis occurs via a transmembrane proton gradient.

[学科分类] 生物化学/生物物理

[关键词] ATP synthesis;Heterodisulfide reductase;Methanogenic bacterium;Vesicle preparation;BES;2-bromoethanesulfonic acid;CoM-SH;2-mercaptoethanesulfonate;CoM-S-S-HTP;heterodisulfide of CoM-SH and HTP-SH;DCCD;N;N'-dicyclohexylcarbodiimide;DES;diethylstilbestrol;HTP-SH;7-mercaptoheptanoylthreonine phosphate;CH3-S-CoM or methyl-CoM;2-(methylthio)ethanesul-fonate;SF 6847;3;5-di-tert-butyl-4-hydroxybenzylidenemalono-nitrile;sulfobetaine;N-tetradecyl-N;N-dimethylammonio-3-propanesulfonate