FIG. 3.

Synonymous codon substitutions in the yopE minimal secretion signal. All possible synonymous substitutions of codons (which do not alter the amino acid specificity) that were not tested in the experiments described in the legend to Fig. 2 were individually introduced at each position from codon 2 to 7 of the yopE minimal secretion signal and fused to npt. Fusions to Npt were analyzed for type III secretion as described in the legend to Fig. 1.