Codon-anticodon interaction at the ribosomal P site improves the accuracy of the decoding process.
The competing incorporation of [14C]Phe (cognate) and [3H]Leu (miscognate) into polypeptide material was measured. Kinetic analysis revealed that at the very beginning of protein synthesis the error fraction was 3 to 10 times larger than the "system-inherent" error, which is the error fraction found on the synthesized proteins. However, if a cognate tRNA, namely either deacylated tRNAPhe or AcPhe-tRNAPhe were prebound to the ribosomal P site, no enhanced error fraction was observed at the beginning. Furthermore, the initial rate of protein synthesis was increased by a factor of 10 to 50, regardless as to whether the ribosomes were precharged with tRNAPhe or AcPhe-tRNAPhe. In contrast, preincubation of ribosomes with non-cognate tRNA such as deacylated tRNALys had no effect. We conclude that codon-anticodon interaction at the P site facilitates the precise exposure of the adjacent codon at the ribosomal A site, thus contributing to the velocity and precision of the decoding process.
D000926:Anticodon / Q000378:metabolism*; D003062:Codon / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D007700:Kinetics; D007930:Leucine / Q000378:metabolism*; D010649:Phenylalanine / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism*
D000926:Anticodon; D003062:Codon; D012333:RNA, Messenger; D012346:RNA, Transfer, Amino Acyl; C006383:tRNA, N-acetylphenylalanine-; D010649:Phenylalanine; D012343:RNA, Transfer; D007930:Leucine