Codon choice and gene expression: synonymous codons differ in translational accuracy.
Ribosomes programmed by different synonymous codons also differ in discriminating among near-cognate aminoacylated tRNAs. In the initial step of the recognition reaction ribosomes programmed by UUC discriminate less well than ribosomes programmed by UUU against ternary complexes containing three types of Leu-tRNA, and ribosomes programmed by CUC discriminate less well than ribosomes programmed by CUU against ternary complexes containing Phe-tRNA. Furthermore, in the proofreading step ribosomes programmed by UUC discriminate less well than ribosomes programmed by UUU against two of three near-cognate Leu-tRNAs, and ribosomes programmed by CUC discriminate less well than ribosomes programmed by CUU against near-cognate Phe-tRNA. The codon-induced change in reaction rate with near-cognate ternary complexes is greater than that with cognate ternary complexes: the most efficient codon is, therefore, the least accurate. Because the efficient, but inaccurate, codon UUC is used preferentially in highly expressed mRNAs of Escherichia coli, maximization of translational accuracy apparently has not been significant in the evolution of this particular biased codon choice in E. coli.
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Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder 80309.
Thompson
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RC
D000926:Anticodon / Q000235:genetics; D001483:Base Sequence; D003062:Codon / Q000235:genetics*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D007700:Kinetics; D010444:Peptide Elongation Factor Tu / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D012343:RNA, Transfer / Q000235:genetics* / Q000378:metabolism; D012356:RNA, Transfer, Leu / Q000378:metabolism; D012360:RNA, Transfer, Phe / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*; D013873:Thionucleotides / Q000378:metabolism
D000926:Anticodon; D003062:Codon; D012333:RNA, Messenger; D012356:RNA, Transfer, Leu; D012360:RNA, Transfer, Phe; D013873:Thionucleotides; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D010444:Peptide Elongation Factor Tu