Molecular basis for bacterial class I release factor methylation by PrmC

Mol Cell. 2005 Dec 22;20(6):917-27. doi: 10.1016/j.molcel.2005.10.025.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Codon, Terminator
  • Crystallography, X-Ray
  • DNA Mutational Analysis
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Methylation
  • Models, Molecular
  • Molecular Sequence Data
  • Multiprotein Complexes
  • Peptide Termination Factors / chemistry*
  • Peptide Termination Factors / genetics
  • Peptide Termination Factors / metabolism
  • Protein Conformation*
  • Protein Methyltransferases / chemistry*
  • Protein Methyltransferases / genetics
  • Protein Methyltransferases / metabolism
  • Sequence Alignment

Substances

  • Bacterial Proteins
  • Codon, Terminator
  • Escherichia coli Proteins
  • Multiprotein Complexes
  • Peptide Termination Factors
  • prfA protein, E coli
  • Protein Methyltransferases
  • prmC protein, E coli

Associated data

  • PDB/2B3T