FIG. 2.—

Analysis of tripeptides encodable by uptake sequences in the genomes of H. influenzae, A. pleuropneumoniae, N. meningitidis, and Escherichia coli. (A) Average frequencies in genomes without the specified uptake sequence of tripeptides encodable by that uptake sequence, plotted against reading-frame usage by each uptake sequence (data from table 2) (R² = 0.30). (B) Codon score for tripeptides encodable by that uptake sequence (calculated as described in Materials and Method) plotted against reading frame usage by each uptake sequence (R² = 0.65). H. influenzae USS, blue diamonds; A. pleuropneumoniae USS, red squares; N. meningitidis DUS, orange triangles.