Visualization of tRNA movements on the Escherichia coli 70S ribosome during the elongation cycle.
Three-dimensional cryomaps have been reconstructed for tRNA-ribosome complexes in pre- and posttranslocational states at 17-A 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-tRNA(f)(Met)-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.
Agrawal
R K
RK
Wadsworth Center, Department of Biomedical Sciences, State University of New York, Albany, New York 12201, USA.
Spahn
C M
CM
Penczek
P
P
Grassucci
R A
RA
Nierhaus
K H
KH
Frank
J
J
D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics*; D007091:Image Processing, Computer-Assisted; D008958:Models, Molecular; D009068:Movement; D010441:Peptide Chain Elongation, Translational; D012343:RNA, Transfer / Q000648:ultrastructure*; D012270:Ribosomes / Q000648:ultrastructure*
D012343:RNA, Transfer