Molecular basis for bacterial class I release factor methylation by PrmC.
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.
Graille
Marc
M
Institut de Biochimie et Biophysique Moléculaire et Cellulaire, CNRS, UMR8619, Université Paris-Sud, Orsay, France.
Heurgué-Hamard
Valérie
V
Champ
Stéphanie
S
Mora
Liliana
L
Scrima
Nathalie
N
Ulryck
Nathalie
N
van Tilbeurgh
Herman
H
Buckingham
Richard H
RH
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
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