title: GTPase activation of elongation factor EF-Tu by the ribosome during decoding.
abstract: We have used single-particle reconstruction in cryo-electron microscopy to determine a structure of the Thermus thermophilus ribosome in which the ternary complex of elongation factor Tu (EF-Tu), tRNA and guanine nucleotide has been trapped on the ribosome using the antibiotic kirromycin. This represents the state in the decoding process just after codon recognition by tRNA and the resulting GTP hydrolysis by EF-Tu, but before the release of EF-Tu from the ribosome. Progress in sample purification and image processing made it possible to reach a resolution of 6.4 A. Secondary structure elements in tRNA, EF-Tu and the ribosome, and even GDP and kirromycin, could all be visualized directly. The structure reveals a complex conformational rearrangement of the tRNA in the A/T state and the interactions with the functionally important switch regions of EF-Tu crucial to GTP hydrolysis. Thus, the structure provides insights into the molecular mechanism of signalling codon recognition from the decoding centre of the 30S subunit to the GTPase centre of EF-Tu.
authors.affiliation: Institut für Medizinische Physik und Biophysik, Charite-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Jan-Christian
authors.initials: JC
authors.lastname: Schuette
authors.forename: Frank V
authors.initials: FV
authors.lastname: Murphy
authors.forename: Ann C
authors.initials: AC
authors.lastname: Kelley
authors.forename: John R
authors.initials: JR
authors.lastname: Weir
authors.forename: Jan
authors.initials: J
authors.lastname: Giesebrecht
authors.forename: Sean R
authors.initials: SR
authors.lastname: Connell
authors.forename: Justus
authors.initials: J
authors.lastname: Loerke
authors.forename: Thorsten
authors.initials: T
authors.lastname: Mielke
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Pawel A
authors.initials: PA
authors.lastname: Penczek
authors.forename: V
authors.initials: V
authors.lastname: Ramakrishnan
authors.forename: Christian M T
authors.initials: CM
authors.lastname: Spahn
mesh_terms: D020285:Cryoelectron Microscopy; D004789:Enzyme Activation; D006153:Guanosine Diphosphate / Q000737:chemistry; D008958:Models, Molecular; D010444:Peptide Elongation Factor Tu / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D017433:Protein Structure, Secondary; D011728:Pyridones / Q000737:chemistry; D012343:RNA, Transfer / Q000737:chemistry / Q000648:ultrastructure; D012270:Ribosomes / Q000737:chemistry / Q000201:enzymology* / Q000648:ultrastructure; D055672:Static Electricity; D016963:Thermus thermophilus / Q000201:enzymology*
chemical_list: D011728:Pyridones; D006153:Guanosine Diphosphate; D012343:RNA, Transfer; D010444:Peptide Elongation Factor Tu; C008536:mocimycin