title: Evidence for the existence in mRNAs of a hairpin element responsible for ribosome dependent pyrrolysine insertion into proteins.
abstract: In the methanogenic archae Methanosarcina barkeri, insertion of pyrrolysine, the 22nd amino acid, results from the decoding of an amber UAG codon in the mRNA of monomethylamine methyltransferases (MtmB). Sequence comparisons combined with structural enzymatic and chemical probing on M. barkeri MtmB1 mRNA demonstrate the presence of a hairpin motif located immediately after the redefined UAG codon. This structure of 86 nucleotides differs slightly from a proposal given in the literature and comprises four successive stems separated by three internal loops and closed by a large apical loop. Sequence alignments of MtmB mRNAs of different Methanosarcinacae reveal a conservation of the motif in both sequence and folding levels. The functional role of this motif as a signal leading to pyrrolysine insertion is discussed.
authors.affiliation: Département Mécanismes et Macromolécules de la Synthèse Protéique et Cristallogenèse, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 15, rue René Descartes, 67084 Strasbourg cedex, France. A.Theobald-dietrich@ibmc.u-strasbg.fr
authors.forename: Anne
authors.initials: A
authors.lastname: Théobald-Dietrich
authors.forename: Richard
authors.initials: R
authors.lastname: Giegé
authors.forename: Joëlle
authors.initials: J
authors.lastname: Rudinger-Thirion
mesh_terms: D019843:Archaeal Proteins / Q000235:genetics*; D001345:Autoradiography; D001483:Base Sequence; D003062:Codon / Q000235:genetics*; D017124:Conserved Sequence; D004251:DNA Transposable Elements; D008239:Lysine / Q000031:analogs & derivatives* / Q000235:genetics; D017021:Methanosarcina barkeri / Q000235:genetics*; D008780:Methyltransferases / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000737:chemistry* / Q000378:metabolism; D012343:RNA, Transfer; D012270:Ribosomes; D016415:Sequence Alignment
chemical_list: D019843:Archaeal Proteins; D003062:Codon; D004251:DNA Transposable Elements; D012333:RNA, Messenger; D012343:RNA, Transfer; D008780:Methyltransferases; C113200:monomethylamine methyltransferase; C456839:pyrrolysine; D008239:Lysine