HMM Summary Page: TIGR02369

Functiontrimethylamine:corrinoid methyltransferase
Gene SymbolmttB
Trusted Cutoff575.35
Domain Trusted Cutoff575.35
Noise Cutoff290.15
Domain Noise Cutoff290.15
Isology Typeequivalog
EC Number2.1.1.250
HMM Length489
AuthorHaft DH
Entry DateNov 4 2004 1:40PM
Last ModifiedFeb 14 2011 3:27PM
CommentThis model represents a distinct subfamily of PF06253. All members here are trimethylamine:corrinoid methyltransferases that contain a critical pyrrolysine residue incorporated during translation via a special tRNA for a TAG (amber) codon. Known members so far are from the genus Methanosarcina. It is one of a suite of three non-homologous enzymes with a critical UAG-encoded pyrrolysine residue in these species (along with dimethylamine methyltransferase and monomethylamine methyltransferase). It demethylates trimethylamine, leaving dimethylamine, and methylates the prosthetic group of its small cognate corrinoid protein, MttC. The methyl group is then transferred by methylcorrinoid:coenzyme M methyltransferase to coenzyme M. Note that the pyrrolysine residue is variously translated as K or X, or as a stop codon that truncates the sequence.
ReferencesDR PFAM; PF06253; MTTB RM 10762254 RT The trimethylamine methyltransferase gene and multiple dimethylamine methyltransferase genes of Methanosarcina barkeri contain in-frame and read-through amber codons. RA Paul L, Ferguson DJ Jr, Krzycki JA. RL J Bacteriol. 2000 May;182(9):2520-9.