title: A novel single amino acid change in small subunit ribosomal protein S5 has profound effects on translational fidelity.
abstract: S5 is a small subunit ribosomal protein (r-protein) linked to the functional center of the 30S ribosomal subunit. In this study we have identified a unique amino acid mutation in Escherichia coli S5 that produces spectinomycin-resistance and cold sensitivity. This mutation significantly alters cell growth, folding of 16S ribosomal RNA, and translational fidelity. While translation initiation is not affected, both +1 and -1 frameshifting and nonsense suppression are greatly enhanced in the mutant strain. Interestingly, this S5 ribosome ambiguity-like mutation is spatially remote from previously identified S5 ribosome ambiguity (ram) mutations. This suggests that the mechanism responsible for ram phenotypes in the novel mutant strain is possibly distinct from those proposed for other known S5 (and S4) ram mutants. This study highlights the importance of S5 in ribosome function and cell physiology, and suggests that translational fidelity can be regulated in multiple ways.
authors.affiliation: Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Narayanaswamy
authors.initials: N
authors.lastname: Kirthi
authors.forename: Biswajoy
authors.initials: B
authors.lastname: Roy-Chaudhuri
authors.forename: Teresa
authors.initials: T
authors.lastname: Kelley
authors.forename: Gloria M
authors.initials: GM
authors.lastname: Culver
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005998:Glycine; D008969:Molecular Sequence Data; D009154:Mutation; D014176:Protein Biosynthesis; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics* / Q000378:metabolism; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D012641:Selection, Genetic; D000198:Spectinomycin / Q000494:pharmacology
chemical_list: D029968:Escherichia coli Proteins; D012336:RNA, Ribosomal, 16S; D012269:Ribosomal Proteins; C030831:ribosomal protein S5; D012343:RNA, Transfer; D000198:Spectinomycin; D005998:Glycine