title: Ribosome recycling factor disassembles the post-termination ribosomal complex independent of the ribosomal translocase activity of elongation factor G.
abstract: Ribosome recycling factor (RRF) disassembles post-termination ribosomal complexes in concert with elongation factor EF-G freeing the ribosome for a new round of polypeptide synthesis. How RRF interacts with EF-G and disassembles post-termination ribosomes is unknown. RRF is structurally similar to tRNA and is therefore thought to bind to the ribosomal A site and be translocated by EF-G during ribosome disassembly as a mimic of tRNA. However, EF-G variants that remain active in GTP hydrolysis but are defective in tRNA translocation fully activate RRF function in vivo and in vitro. Furthermore, RRF and the GTP form of EF-G do not co-occupy the terminating ribosome in vitro; RRF is ejected by EF-G from the preformed complex. These findings suggest that RRF is not a functional mimic of tRNA and disassembles the post-termination ribosomal complex independently of the translocation activity of EF-G.
authors.affiliation: Department of Basic Medical Sciences, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Koichi
authors.initials: K
authors.lastname: Ito
authors.forename: Tohru
authors.initials: T
authors.lastname: Yamami
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Nakamura
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000502:physiology; D005798:Genes, Bacterial; D020043:Genes, Essential; D006160:Guanosine Triphosphate / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D020653:Peptide Elongation Factor G / Q000235:genetics / Q000502:physiology*; D011485:Protein Binding; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D012343:RNA, Transfer / Q000378:metabolism; D012269:Ribosomal Proteins; D012270:Ribosomes / Q000378:metabolism / Q000502:physiology
chemical_list: D029968:Escherichia coli Proteins; D020653:Peptide Elongation Factor G; D011506:Proteins; D012269:Ribosomal Proteins; C087267:ribosome releasing factor; D006160:Guanosine Triphosphate; D012343:RNA, Transfer