TY - JOUR
T1 - Tuning the affinity of aminoacyl-tRNA to elongation factor Tu for optimal decoding
AU - Schrader, Jared M.
AU - Chapman, Stephen J.
AU - Uhlenbeck, Olke C.
PY - 2011/3/29
Y1 - 2011/3/29
N2 - To better understand why aminoacyl-tRNAs (aa-tRNAs) have evolved to bind bacterial elongation factor Tu (EF-Tu) with uniform affinities, mutant tRNAs with differing affinities for EF-Tu were assayed for decoding on Escherichia coli ribosomes. At saturating EF-Tu concentrations, weaker-binding aa-tRNAs decode their cognate codons similarly to wild-type tRNAs. However, tighter-binding aa-tRNAs show reduced rates of peptide bond formation due to slow release from EF-Tu•GDP. Thus, the affinities of aa-tRNAs for EF-Tu are constrained to be uniform by their need to bind tightly enough to form the ternary complex but weakly enough to release from EF-Tu during decoding. Consistent with available crystal structures, the identity of the esterified amino acid and three base pairs in the T stem of tRNA combine to define the affinity of each aa-tRNA for EF-Tu, both off and on the ribosome.
AB - To better understand why aminoacyl-tRNAs (aa-tRNAs) have evolved to bind bacterial elongation factor Tu (EF-Tu) with uniform affinities, mutant tRNAs with differing affinities for EF-Tu were assayed for decoding on Escherichia coli ribosomes. At saturating EF-Tu concentrations, weaker-binding aa-tRNAs decode their cognate codons similarly to wild-type tRNAs. However, tighter-binding aa-tRNAs show reduced rates of peptide bond formation due to slow release from EF-Tu•GDP. Thus, the affinities of aa-tRNAs for EF-Tu are constrained to be uniform by their need to bind tightly enough to form the ternary complex but weakly enough to release from EF-Tu during decoding. Consistent with available crystal structures, the identity of the esterified amino acid and three base pairs in the T stem of tRNA combine to define the affinity of each aa-tRNA for EF-Tu, both off and on the ribosome.
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U2 - 10.1073/pnas.1102128108
DO - 10.1073/pnas.1102128108
M3 - Article
C2 - 21402928
AN - SCOPUS:79955113244
SN - 0027-8424
VL - 108
SP - 5215
EP - 5220
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 13
ER -