title: Multiple effects of S13 in modulating the strength of intersubunit interactions in the ribosome during translation.
abstract: The ribosomal protein S13 is found in the head region of the small subunit, where it interacts with the central protuberance of the large ribosomal subunit and with the P site-bound tRNA through its extended C terminus. The bridging interactions between the large and small subunits are dynamic, and are thought to be critical in orchestrating the molecular motions of the translation cycle. S13 provides a direct link between the tRNA-binding site and the movements in the head of the small subunit seen during translocation, thereby providing a possible pathway of signal transduction. We have created and characterized an rpsM(S13)-deficient strain of Escherichia coli and have found significant defects in subunit association, initiation and translocation through in vitro assays of S13-deficient ribosomes. Targeted mutagenesis of specific bridge and tRNA contact elements in S13 provides evidence that these two interaction domains play critical roles in maintaining the fidelity of translation. This ribosomal protein thus appears to play a non-essential, yet important role by modulating subunit interactions in multiple steps of the translation cycle.
authors.affiliation: Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Cukras
authors.forename: Rachel
authors.initials: R
authors.lastname: Green
mesh_terms: D001681:Biological Assay; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D009154:Mutation; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis / Q000502:physiology*; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*; D001616:beta-Galactosidase
chemical_list: D029968:Escherichia coli Proteins; D012269:Ribosomal Proteins; C512838:rpsM protein, E coli; D001616:beta-Galactosidase