title: Incorporation of aminoacyl-tRNA into the ribosome as seen by cryo-electron microscopy.
abstract: Aminoacyl-tRNAs (aa-tRNAs) are delivered to the ribosome as part of the ternary complex of aa-tRNA, elongation factor Tu (EF-Tu) and GTP. Here, we present a cryo-electron microscopy (cryo-EM) study, at a resolution of approximately 9 A, showing that during the incorporation of the aa-tRNA into the 70S ribosome of Escherichia coli, the flexibility of aa-tRNA allows the initial codon recognition and its accommodation into the ribosomal A site. In addition, a conformational change observed in the GTPase-associated center (GAC) of the ribosomal 50S subunit may provide the mechanism by which the ribosome promotes a relative movement of the aa-tRNA with respect to EF-Tu. This relative rearrangement seems to facilitate codon recognition by the incoming aa-tRNA, and to provide the codon-anticodon recognition-dependent signal for the GTPase activity of EF-Tu. From these new findings we propose a mechanism that can explain the sequence of events during the decoding of mRNA on the ribosome.
authors.affiliation: Howard Hughes Medical Institute, Health Research, Inc. at the Wadsworth Center, Empire State Plaza, Albany, New York 12201-0509, USA.
authors.forename: Mikel
authors.initials: M
authors.lastname: Valle
authors.forename: Andrey
authors.initials: A
authors.lastname: Zavialov
authors.forename: Wen
authors.initials: W
authors.lastname: Li
authors.forename: Scott M
authors.initials: SM
authors.lastname: Stagg
authors.forename: Jayati
authors.initials: J
authors.lastname: Sengupta
authors.forename: Rikke C
authors.initials: RC
authors.lastname: Nielsen
authors.forename: Poul
authors.initials: P
authors.lastname: Nissen
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Harvey
authors.forename: Måns
authors.initials: M
authors.lastname: Ehrenberg
authors.forename: Joachim
authors.initials: J
authors.lastname: Frank
mesh_terms: D020285:Cryoelectron Microscopy; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D020558:GTP Phosphohydrolases / Q000378:metabolism; D009690:Nucleic Acid Conformation; D017434:Protein Structure, Tertiary; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism* / Q000648:ultrastructure; D012270:Ribosomes / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D012346:RNA, Transfer, Amino Acyl; D020558:GTP Phosphohydrolases