title: A new UAG-encoded residue in the structure of a methanogen methyltransferase.
abstract: Genes encoding methanogenic methylamine methyltransferases all contain an in-frame amber (UAG) codon that is read through during translation. We have identified the UAG-encoded residue in a 1.55 angstrom resolution structure of the Methanosarcina barkeri monomethylamine methyltransferase (MtmB). This structure reveals a homohexamer comprised of individual subunits with a TIM barrel fold. The electron density for the UAG-encoded residue is distinct from any of the 21 natural amino acids. Instead it appears consistent with a lysine in amide-linkage to (4R,5R)-4-substituted-pyrroline-5-carboxylate. We suggest that this amino acid be named l-pyrrolysine.
authors.affiliation: Department of Biochemistry, The Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA.
authors.forename: Bing
authors.initials: B
authors.lastname: Hao
authors.forename: Weimin
authors.initials: W
authors.lastname: Gong
authors.forename: Tsuneo K
authors.initials: TK
authors.lastname: Ferguson
authors.forename: Carey M
authors.initials: CM
authors.lastname: James
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Krzycki
authors.forename: Michael K
authors.initials: MK
authors.lastname: Chan
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D003062:Codon; D003460:Crystallization; D018360:Crystallography, X-Ray; D019281:Dimerization; D019766:Genes, Archaeal; D006860:Hydrogen Bonding; D008239:Lysine / Q000031:analogs & derivatives / Q000737:chemistry / Q000235:genetics*; D017021:Methanosarcina barkeri / Q000201:enzymology* / Q000235:genetics; D008744:Methylamines / Q000378:metabolism; D008780:Methyltransferases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D008958:Models, Molecular; D008970:Molecular Weight; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D003062:Codon; D008744:Methylamines; C095091:MtmC1 protein, Methanosarcina barkeri; C027451:methylamine; D008780:Methyltransferases; C113200:monomethylamine methyltransferase; C456839:pyrrolysine; D008239:Lysine