FIG. 7.

Comparison of the yopQ and yopE mRNA type III secretion signals. Nucleotides that comprise the minimal secretion signals of yopQ and yopE are shown in red, and those comprising the suppressor region are shown in blue. Amino acids encoded by the each codon are indicated above the codon using single-letter abbreviations. Nucleotides that are sensitive to mutagenesis are underlined, and codons that contain critical nucleotides are highlighted in yellow. The boundary beyond which frameshift mutations are tolerated for yopQ and yopE secretion signals, codon 13, is also shown.