Fig. S2.

PheRS editing-dependent reduction of pheA expression is caused by the translation of the PheL gene past residue 6. β-Galactosidase activity from a F6/stop mutant pheA′-lacZ reporter was monitored as described in the Materials and Methods and was determined for both the wild-type pheT (solid bars) and pheT(G318W) (checkered bars) strains at late log phase. Activity from cultures grown in M9 minimal medium containing 100 µM Phe or 10 µM m-Tyr is shown. Error bars represent the SD from three independent experiments.