title: How the ribosome hands the A-site tRNA to the P site during EF-G-catalyzed translocation.
abstract: Coupled translocation of messenger RNA and transfer RNA (tRNA) through the ribosome, a process catalyzed by elongation factor EF-G, is a crucial step in protein synthesis. The crystal structure of a bacterial translocation complex describes the binding states of two tRNAs trapped in mid-translocation. The deacylated P-site tRNA has moved into a partly translocated pe/E chimeric hybrid state. The anticodon stem-loop of the A-site tRNA is captured in transition toward the 30S P site, while its 3' acceptor end contacts both the A and P loops of the 50S subunit, forming an ap/ap chimeric hybrid state. The structure shows how features of ribosomal RNA rearrange to hand off the A-site tRNA to the P site, revealing an active role for ribosomal RNA in the translocation process.
authors.affiliation: Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Lancaster
authors.affiliation: Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA.
authors.forename: John Paul
authors.initials: JP
authors.lastname: Donohue
authors.affiliation: Center for Molecular Biology of RNA and Department of Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA. harry@nuvolari.ucsc.edu.
authors.forename: Harry F
authors.initials: HF
authors.lastname: Noller
mesh_terms: D000926:Anticodon / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D018360:Crystallography, X-Ray; D009690:Nucleic Acid Conformation; D020653:Peptide Elongation Factor G / Q000737:chemistry* / Q000378:metabolism; D014176:Protein Biosynthesis; D011487:Protein Conformation; D012333:RNA, Messenger / Q000737:chemistry* / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry* / Q000378:metabolism; D054681:Ribosome Subunits, Large, Bacterial / Q000737:chemistry* / Q000378:metabolism; D016963:Thermus thermophilus
chemical_list: D000926:Anticodon; D020653:Peptide Elongation Factor G; D012333:RNA, Messenger; D012343:RNA, Transfer