FIG 2.

AlaRS fidelity is required for optimal growth in E. coli. (A) AaRS mutants and the AlaRS C666A complement strain (pLK-alaS) were grown in LB, and their growth was monitored. In rich medium, AlaRS fidelity is required for optimal growth. (B) AlaRS C666A was grown in M9 minimal medium supplemented with exogenous amino acids to determine the toxicity of noncognate stress. (C) Serine mistranslation was observed in the AlaRS C666A mutant using a β-lactamase S68A mistranslation reporter. (D) The severity of the AlaRS C666A growth defect was enhanced when grown at 42°C. All growth experiments were performed in triplicate, and error bars indicate the standard deviation of the replicates. WT, wild type.