During translation, a conserved GTPase elongation factor-EF-G in bacteria or eEF2 in eukaryotes-translocates tRNA and mRNA through the ribosome. EF-G has been proposed to act as a flexible motor that propels tRNA and mRNA movement, as a rigid pawl that biases unidirectional translocation resulting from ribosome rearrangements, or by various combinations of motor- and pawl-like mechanisms. Using time-resolved cryo-EM, we visualized GTP-catalyzed translocation without inhibitors, capturing elusive structures of ribosome•EF-G intermediates at near-atomic resolution. Prior to translocation, EF-G binds near peptidyl-tRNA, while the rotated 30S subunit stabilizes the EF-G GTPase center. Reverse 30S rotation releases Pi and translocates peptidyl-tRNA and EF-G by ~20 Å. An additional 4-Å translocation initiates EF-G dissociation from a transient ribosome state with highly swiveled 30S head. The structures visualize how nearly rigid EF-G rectifies inherent and spontaneous ribosomal dynamics into tRNA-mRNA translocation, whereas GTP hydrolysis and Pi release drive EF-G dissociation.
- MeSH
- RNA, Transfer, Amino Acyl metabolism MeSH
- Cryoelectron Microscopy * MeSH
- Peptide Elongation Factor G chemistry metabolism MeSH
- Escherichia coli chemistry metabolism MeSH
- Phosphates metabolism MeSH
- Guanosine Triphosphate chemistry metabolism MeSH
- Ribosome Subunits, Small, Bacterial chemistry metabolism MeSH
- RNA, Messenger metabolism MeSH
- Protein Biosynthesis MeSH
- Ribosomes chemistry metabolism MeSH
- RNA, Transfer metabolism MeSH
- Protein Binding MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
... Covalent Bonds and Noncovalent -- Interactions 32 -- The Electronic Structure of an Atom Determines the ... ... -- Number and Geometry of Covalent Bonds It Can Make 33 -- CONTENTS -- XV -- Electrons May Be Shared ... ... Releases the -- Energy Stored in NADH and FADH2 493 -- Electron Transport in Mitochondria Is Coupled ... ... 494 -- Reduction Potentials of Electron Carriers Favor -- Electron Flow from NADH to 02 499 -- Experiments ... ... 610 -- The Endocytic Pathway Delivers Iron to Cells without Dissociation of the Receptor-Transferrin ...
6th ed. xxxvii, 1150 s. : il., tab. ; 29 cm
- MeSH
- Cell Biology MeSH
- Molecular Biology MeSH
- Publication type
- Monograph MeSH
- Conspectus
- Biochemie. Molekulární biologie. Biofyzika
- NML Fields
- biologie
- cytologie, klinická cytologie
... Greater Amount of Usable Energy -- Metabolism Is Dominated by the Citric Acid Cycle The Transfer of Electrons ... ... Cells Can Be Seen in a Phase-Contrast or Differential-Interference-Contrast Microscope 146 -- The Electron ... ... and Freeze-Etch Electron Microscopy -- Provide Novel Views of the Cell 152 -- Individual Macromolecules ... ... Can Be Resolved in the -- Electron Microscope 154 -- The Detailed Structure of Molecules in a Crystalline ... ... Transport from ATP Synthesis 508 -- Respiratory Control Normally Restrains the Electron -- Flow Through ...
xxxix, 1146 s. : il., tab. ; 28 cm
- MeSH
- Cell Biology MeSH
- Molecular Biology MeSH
- Publication type
- Monograph MeSH
- Conspectus
- Biochemie. Molekulární biologie. Biofyzika
- NML Fields
- biologie
- cytologie, klinická cytologie
