Translation is a non-uniform process: Effect of tRNA availability on the rate of elongation of nascent polypeptide chains

摘要: We reported elsewhere (Varenne et al., 1982) that, during synthesis of a number colicins in Escherichia coli, intermediate nascent chains discrete sizes accumulated, suggesting variable rate translation. In this paper, detailed analysis provides arguments that phenomenon, at least for the proteins under study, is not related to aspects messenger RNA such as secondary structure. It linked difference transfer availability various codons. Experimental translation other E. coli confirms main origin discontinuous polypeptide elongation cycle following. For given codon, stochastic search cognate ternary complex (aminoacyl-tRNA-EF-Tu-GTP) rate-limiting step cycle: transpeptidation and translocation steps are much faster. The degree slackening ribosome movement almost proportional inverse tRNA concentrations. verification model its possible physiological significance discussed.