Hence, all methylamine corrinoid methyltransferases (MttB, MtbB, and MtmB) possess the 22nd proteogenic amino acid pyrrolysine .
The genes mttC and mtbC are part of a large gene cluster containing the corresponding mttB and mtbB genes as well as genes encoding potential permeases for TMA and DMA uptake, respectively (Figure 7).
We identified the presence of genes for methanogenesis from methanol and also from dimethylsulfide and methylamines in the two other sequenced genomes ("Candidatus Methanomethylophilus alvus" , "Candidatus Methanomassiliicoccus intestinalis" ), together with the Pyl-coding genes and in-frame amber codon in the mtmB, mtbB, and mttB genes of these three species.
Usually, these genes are closely associated with the methylamines MT genes (mtmB, mtbB, and mttB) and other genes involved in these pathways (which do not encode Pyl-containing proteins).
These include, for the three genomes available and analyzed to date, at least the global presence of all the genes for Pyl synthesis, charging and cotranslational incorporation, in cooccurrence with all the genes for methylotrophic methanogenesis from methylamines, that is, those coding for methylamines-corrinoid protein methyltransferases (MT) genes (mtmB, mtbB, and mttB) all bearing an in-frame amber codon.