FIG. 2.

Growth curves E. coli KL231 in the presence of toxic levels of nonleucine amino acids. Transformed E. coli KL231 was prepared, and its growth rates were measured as previously described (12). E. coli KL231 harboring wild-type (▪) or the TT/VV editing-defective mutant (▴) LeuRS was grown in liquid minimal medium that contained 16 mM of the following amino acids: (A) leucine, (B) methionine, (C) valine, (D) norleucine, (E) homocysteine, (F) homoserine, and (G) norvaline. Error bars are based on assays that were repeated in triplicate and are present for each point.