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© The Rockefeller University Press,
0021-9525/2000//447 $5.00
The Journal of Cell Biology, Volume 150, Number 3,
, 2000 447-460
Original Article |
Visualization of Trna Movements on the Escherichia coli 70s Ribosome during the Elongation Cycle
joachim{at}wadsworth.org
Three-dimensional cryomaps have been reconstructed for tRNA–ribosome complexes in pre- and posttranslocational states at 17-Å resolution. The positions of tRNAs in the A and P sites in the pretranslocational complexes and in the P and E sites in the posttranslocational complexes have been determined. Of these, the P-site tRNA position is the same as seen earlier in the initiation-like fMet-tRNAfMet-ribosome complex, where it was visualized with high accuracy. Now, the positions of the A- and E-site tRNAs are determined with similar accuracy. The positions of the CCA end of the tRNAs at the A site are different before and after peptide bond formation. The relative positions of anticodons of P- and E-site tRNAs in the posttranslocational state are such that a codon–anticodon interaction at the E site appears feasible.
Key Words: ribosomes protein synthesis tRNA-binding sites cryoelectron microscopy elongation cycle
© 2000 The Rockefeller University Press
Abbreviations used in this paper: 3D, three-dimensional; ASL, anticodon stem-loop; cryo-EM, cryoelectron microscopy; EF-G, elongation factor G; EF-Tu, elongation factor Tu; MF-mRNA, 46-nt long mRNA with AUG and UUC codon in its middle; POST, posttranslocational; PRE, pretranslocational.
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