title: Molecular basis for bacterial class I release factor methylation by PrmC.
abstract: Class I release factors bind to ribosomes in response to stop codons and trigger peptidyl-tRNA hydrolysis at the P site. Prokaryotic and eukaryotic RFs share one motif: a GGQ tripeptide positioned in a loop at the end of a stem region that interacts with the ribosomal peptidyl transferase center. The glutamine side chain of this motif is specifically methylated in both prokaryotes and eukaryotes. Methylation in E. coli is due to PrmC and results in strong stimulation of peptide chain release. We have solved the crystal structure of the complex between E. coli RF1 and PrmC bound to the methyl donor product AdoHCy. Both the GGQ domain (domain 3) and the central region (domains 2 and 4) of RF1 interact with PrmC. Structural and mutagenic data indicate a compact conformation of RF1 that is unlike its conformation when it is bound to the ribosome but is similar to the crystal structure of the protein alone.
authors.affiliation: Institut de Biochimie et Biophysique Moléculaire et Cellulaire, CNRS, UMR8619, Université Paris-Sud, Orsay, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Graille
authors.forename: Valérie
authors.initials: V
authors.lastname: Heurgué-Hamard
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Champ
authors.forename: Liliana
authors.initials: L
authors.lastname: Mora
authors.forename: Nathalie
authors.initials: N
authors.lastname: Scrima
authors.forename: Nathalie
authors.initials: N
authors.lastname: Ulryck
authors.forename: Herman
authors.initials: H
authors.lastname: van Tilbeurgh
authors.forename: Richard H
authors.initials: RH
authors.lastname: Buckingham
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018388:Codon, Terminator; D018360:Crystallography, X-Ray; D004252:DNA Mutational Analysis; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008745:Methylation; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D010454:Peptide Termination Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D011496:Protein Methyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D018388:Codon, Terminator; D029968:Escherichia coli Proteins; D046912:Multiprotein Complexes; D010454:Peptide Termination Factors; C489005:prfA protein, E coli; D011496:Protein Methyltransferases; C092404:prmC protein, E coli