title: Crystal structure of release factor RF3 trapped in the GTP state on a rotated conformation of the ribosome.
abstract: The class II release factor RF3 is a GTPase related to elongation factor EF-G, which catalyzes release of class I release factors RF1 and RF2 from the ribosome after termination of protein synthesis. The 3.3 Å crystal structure of the RF3·GDPNP·ribosome complex provides a high-resolution description of interactions and structural rearrangements that occur when binding of this translational GTPase induces large-scale rotational movements in the ribosome. RF3 induces a 7° rotation of the body and 14° rotation of the head of the 30S ribosomal subunit, and itself undergoes inter- and intradomain conformational rearrangements. We suggest that ordering of critical elements of switch loop I and the P loop, which help to form the GTPase catalytic site, are caused by interactions between the G domain of RF3 and the sarcin-ricin loop of 23S rRNA. The rotational movements in the ribosome induced by RF3, and its distinctly different binding orientation to the sarcin-ricin loop of 23S rRNA, raise interesting implications for the mechanism of action of EF-G in translocation.
authors.affiliation: Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, CA 95064, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.forename: Laura
authors.initials: L
authors.lastname: Lancaster
authors.forename: Sergei
authors.initials: S
authors.lastname: Trakhanov
authors.forename: Harry F
authors.initials: HF
authors.lastname: Noller
mesh_terms: D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000737:chemistry / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D020653:Peptide Elongation Factor G / Q000378:metabolism; D010454:Peptide Termination Factors / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D014176:Protein Biosynthesis / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects; D012338:RNA, Ribosomal, 23S / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry* / Q000378:metabolism; D014178:Translocation, Genetic / Q000187:drug effects / Q000235:genetics; D014756:Viomycin / Q000494:pharmacology
chemical_list: D029968:Escherichia coli Proteins; D020653:Peptide Elongation Factor G; D010454:Peptide Termination Factors; D012338:RNA, Ribosomal, 23S; C489007:prfC protein, E coli; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases; D014756:Viomycin