title: Role of the ribosomal P-site elements of m²G966, m⁵C967, and the S9 C-terminal tail in maintenance of the reading frame during translational elongation in Escherichia coli.
abstract: The ribosomal P-site hosts the peptidyl-tRNAs during translation elongation. Which P-site elements support these tRNA species to maintain codon-anticodon interactions has remained unclear. We investigated the effects of P-site features of methylations of G966, C967, and the conserved C-terminal tail sequence of Ser, Lys, and Arg (SKR) of the S9 ribosomal protein in maintenance of the translational reading frame of an mRNA. We generated Escherichia coli strains deleted for the SKR sequence in S9 ribosomal protein, RsmB (which methylates C967), and RsmD (which methylates G966) and used them to translate LacZ from its +1 and -1 out-of-frame constructs. We show that the S9 SKR tail prevents both the +1 and -1 frameshifts and plays a general role in holding the P-site tRNA/peptidyl-tRNA in place. In contrast, the G966 and C967 methylations did not make a direct contribution to the maintenance of the translational frame of an mRNA. However, deletion of rsmB in the S9Δ3 background caused significantly increased -1 frameshifting at 37°C. Interestingly, the effects of the deficiency of C967 methylation were annulled when the E. coli strain was grown at 30°C, supporting its context-dependent role.
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.
authors.forename: Smriti
authors.initials: S
authors.lastname: Arora
authors.forename: Satya Prathyusha
authors.initials: SP
authors.lastname: Bhamidimarri
authors.forename: Michael H W
authors.initials: MH
authors.lastname: Weber
authors.forename: Umesh
authors.initials: U
authors.lastname: Varshney
mesh_terms: D000595:Amino Acid Sequence; D003062:Codon; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D016368:Frameshift Mutation; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D008745:Methylation; D008958:Models, Molecular; D010441:Peptide Chain Elongation, Translational / Q000502:physiology*; D011487:Protein Conformation; D012270:Ribosomes; D016963:Thermus thermophilus / Q000235:genetics / Q000378:metabolism
chemical_list: D003062:Codon; D029968:Escherichia coli Proteins