Publication Date:
2010-07-16
Description:
The translocation step of protein synthesis entails large-scale rearrangements of the ribosome-transfer RNA (tRNA) complex. Here we have followed tRNA movement through the ribosome during translocation by time-resolved single-particle electron cryomicroscopy (cryo-EM). Unbiased computational sorting of cryo-EM images yielded 50 distinct three-dimensional reconstructions, showing the tRNAs in classical, hybrid and various novel intermediate states that provide trajectories and kinetic information about tRNA movement through the ribosome. The structures indicate how tRNA movement is coupled with global and local conformational changes of the ribosome, in particular of the head and body of the small ribosomal subunit, and show that dynamic interactions between tRNAs and ribosomal residues confine the path of the tRNAs through the ribosome. The temperature dependence of ribosome dynamics reveals a surprisingly flat energy landscape of conformational variations at physiological temperature. The ribosome functions as a Brownian machine that couples spontaneous conformational changes driven by thermal energy to directed movement.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fischer, Niels -- Konevega, Andrey L -- Wintermeyer, Wolfgang -- Rodnina, Marina V -- Stark, Holger -- England -- Nature. 2010 Jul 15;466(7304):329-33. doi: 10.1038/nature09206.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉3D Electron Cryomicroscopy Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Gottingen, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20631791" target="_blank"〉PubMed〈/a〉
Keywords:
Cryoelectron Microscopy
;
Escherichia coli
;
Kinetics
;
Models, Molecular
;
Molecular Conformation
;
*Movement
;
*Protein Biosynthesis
;
RNA, Transfer/genetics/*metabolism
;
Ribosome Subunits, Large, Bacterial/chemistry/metabolism
;
Ribosome Subunits, Small, Bacterial/chemistry/metabolism
;
Ribosomes/chemistry/*metabolism
;
Temperature
;
Thermodynamics
;
Time Factors
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
