Abstract
Following the observation of lysine for arginine misincorporation at the poor choice codon arg-AGA, a comparison of codon usage patterns for highly expressed mRNA''s in Escherichia coli provides a basis for the proposal that the major codon preference is subject to mistranslational constraints. In addition, the codon are utilized, as well as arranged, to provide a hydropathically conservative amino acid as the most probable replacement resulting from a mistranslational event.