Codon specificity of starvation induced misreading.

Mistranslated derivatives of the coat protein of the bacteriophage MS2 were isolated from infected cells starved for asparagine. This protein contains a high level of lysine for asparagine substitutions. By peptide analysis and amino acid sequencing we show that there is a six-fold greater frequency of errors at AAU codons than at AAC codons. This ratio is the same as that found in unstarved cells where the overall error frequency is 100-fold less. We also demonstrate that, at least for AAC codons, context affects error frequency.