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Function of Ech Hydrogenase in Ferredoxin-Dependent, Membrane-Bound Electron Transport in Methanosarcina mazei

2009; American Society for Microbiology; Volume: 192; Issue: 3 Linguagem: Inglês

10.1128/jb.01307-09

1098-5530

Cornelia U. Welte, Verena Kallnik, Marcel Grapp, Güneş Bender, Steve W. Ragsdale, Uwe Deppenmeier,

Metal-Catalyzed Oxygenation Mechanisms

Reduced ferredoxin is an intermediate in the methylotrophic and aceticlastic pathway of methanogenesis and donates electrons to membrane-integral proteins, which transfer electrons to the heterodisulfide reductase. A ferredoxin interaction has been observed previously for the Ech hydrogenase. Here we present a detailed analysis of a Methanosarcina mazei Delta ech mutant which shows decreased ferredoxin-dependent membrane-bound electron transport activity, a lower growth rate, and faster substrate consumption. Evidence is presented that a second protein whose identity is unknown oxidizes reduced ferredoxin, indicating an involvement in methanogenesis from methylated C(1) compounds.