title: Methylation of class I translation termination factors: structural and functional aspects.
abstract: During protein synthesis, release of polypeptide from the ribosome occurs when an in frame termination codon is encountered. Contrary to sense codons, which are decoded by tRNAs, stop codons present in the A-site are recognized by proteins named class I release factors, leading to the release of newly synthesized proteins. Structures of these factors bound to termination ribosomal complexes have recently been obtained, and lead to a better understanding of stop codon recognition and its coordination with peptidyl-tRNA hydrolysis in bacteria. Release factors contain a universally conserved GGQ motif which interacts with the peptidyl-transferase centre to allow peptide release. The Gln side chain from this motif is methylated, a feature conserved from bacteria to man, suggesting an important biological role. However, methylation is catalysed by completely unrelated enzymes. The function of this motif and its post-translational modification will be discussed in the context of recent structural and functional studies.
authors.affiliation: IBBMC, Université Paris-Sud 11, CNRS UMR8619, Orsay Cedex, F-91405, France. marc.graille@u-psud.fr
authors.forename: Marc
authors.initials: M
authors.lastname: Graille
authors.forename: Sabine
authors.initials: S
authors.lastname: Figaro
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Kervestin
authors.forename: Richard H
authors.initials: RH
authors.lastname: Buckingham
authors.forename: Dominique
authors.initials: D
authors.lastname: Liger
authors.forename: Valérie
authors.initials: V
authors.lastname: Heurgué-Hamard
mesh_terms: D000818:Animals; D006801:Humans; D008745:Methylation; D010443:Peptide Chain Termination, Translational; D010454:Peptide Termination Factors / Q000737:chemistry* / Q000378:metabolism*; D012359:tRNA Methyltransferases / Q000378:metabolism
chemical_list: D010454:Peptide Termination Factors; D012359:tRNA Methyltransferases