title: The energy conserving methyltetrahydromethanopterin:coenzyme M methyltransferase complex from methanogenic archaea: function of the subunit MtrH.
abstract: In methanogenic archaea the transfer of the methyl group of N5-methyltetrahydromethanopterin to coenzyme M is coupled with energy conservation. The reaction is catalyzed by a membrane associated multienzyme complex composed of eight different subunits MtrA-H. The 23 kDa subunit MtrA harbors a corrinoid prosthetic group which is methylated and demethylated in the catalytic cycle. We report here that the 34 kDa subunit MtrH catalyzes the methylation reaction. MtrH was purified and shown to exhibit methyltetrahydromethanopterin:cob(I)alamin methyltransferase activity. Sequence comparison revealed similarity of MtrH with MetH from Escherichia coli and AcsE from Clostridium thermoaceticum: both enzymes exhibit methyltetrahydrofolate:cob(I)alamin methyltransferase activity.
authors.affiliation: Max-Planck-Institut für terrestrische Mikrobiologie and Laboratorium für Mikrobiologie des Fachbereichs Biologie der Philipps-Universität, Marburg, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Hippler
authors.forename: R K
authors.initials: RK
authors.lastname: Thauer
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D004734:Energy Metabolism; D007506:Iron-Sulfur Proteins / Q000378:metabolism; D017014:Methanobacterium / Q000201:enzymology*; D008780:Methyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011622:Pterins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013763:Tetrahydrofolates / Q000378:metabolism; D014805:Vitamin B 12 / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C080269:C-Fe-SP protein, Moorella thermoacetica; D007506:Iron-Sulfur Proteins; D011622:Pterins; D013763:Tetrahydrofolates; C073313:5-methyl-5,6,7,8-tetrahydro-methanopterin; C019476:mecobalamin; D008780:Methyltransferases; C048755:tetrahydromethanopterin S-methyltransferase; D014805:Vitamin B 12; C005984:5-methyltetrahydrofolate