Uniform binding of aminoacylated transfer RNAs to the ribosomal A and P sites.
The association and dissociation rate constants of eight different E. coli aminoacyl-tRNAs (aa-tRNAs) for E. coli ribosomes programmed with mRNAs of defined sequences were determined. Identical association and dissociation rate constants were observed for all eight aa-tRNAs in both the ribosomal A and P sites despite substantial differences in tRNA sequence, the type of esterified amino acid, and posttranscriptional modifications. These results indicate that the overall binding of all aa-tRNAs to the ribosome is uniform. However, when either the esterified amino acid or the tRNA modifications were removed, binding was no longer uniform. These results suggest that differences in tRNA sequences and tRNA modifications have evolved to offset differential thermodynamic contributions of the esterified amino acid and the codon-anticodon interaction so that ribosomal binding of all aa-tRNAs remains uniform.
Fahlman
Richard P
RP
Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 60208, USA.
Dale
Taraka
T
Uhlenbeck
Olke C
OC
D004926:Escherichia coli / Q000378:metabolism; D007700:Kinetics; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011487:Protein Conformation; D012333:RNA, Messenger / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry* / Q000378:metabolism; D012270:Ribosomes / Q000737:chemistry / Q000378:metabolism; D013696:Temperature; D013997:Time Factors; D046249:Transfer RNA Aminoacylation
D012333:RNA, Messenger; D012343:RNA, Transfer