Resampling and editing of mischarged tRNA prior to translation elongation.
Faithful translation of the genetic code depends on the GTPase EF-Tu delivering correctly charged aminoacyl-tRNAs to the ribosome for pairing with cognate codons. The accurate coupling of cognate amino acids and tRNAs by the aminoacyl-tRNA synthetases is achieved through a combination of substrate specificity and product editing. Once released by aminoacyl-tRNA synthetases, both cognate and near-cognate aminoacyl-tRNAs were considered to be committed to ribosomal protein synthesis through their association with EF-Tu. Here we show instead that aminoacyl-tRNAs in ternary complex with EF-Tu*GTP can readily dissociate and rebind to aminoacyl-tRNA synthetases. For mischarged species, this allows resampling by the product editing pathway, leading to a reduction in the overall error rate of aminoacyl-tRNA synthesis. Resampling of mischarged tRNAs was shown to increase the accuracy of translation over ten fold during in vitro protein synthesis, supporting the presence of an additional quality control step prior to translation elongation.
Ling
Jiqiang
J
Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA.
So
Byung Ran
BR
Yadavalli
Srujana S
SS
Roy
Hervé
H
Shoji
Shinichiro
S
Fredrick
Kurt
K
Musier-Forsyth
Karin
K
Ibba
Michael
M
D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000378:metabolism*; D005815:Genetic Code; D006160:Guanosine Triphosphate / Q000378:metabolism*; D007700:Kinetics; D007935:Leucine-tRNA Ligase / Q000378:metabolism; D009690:Nucleic Acid Conformation; D010441:Peptide Chain Elongation, Translational; D010444:Peptide Elongation Factor Tu / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D010652:Phenylalanine-tRNA Ligase / Q000378:metabolism; D012329:RNA, Bacterial; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism*; D013379:Substrate Specificity; D046249:Transfer RNA Aminoacylation; D014448:Tyrosine-tRNA Ligase / Q000378:metabolism
D029968:Escherichia coli Proteins; D010455:Peptides; D012329:RNA, Bacterial; C012001:polyphenylalanine; C017663:polytyrosine; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D010444:Peptide Elongation Factor Tu; D000604:Amino Acyl-tRNA Synthetases; D014448:Tyrosine-tRNA Ligase; D010652:Phenylalanine-tRNA Ligase; D007935:Leucine-tRNA Ligase