FIG. 1.

L. monocytogenes genes encoding chitinases and chitin binding proteins. (A) chiA (lmo1883) encodes a chitinase of 352 amino acids, chiB (lmo0105) encodes a chitinase of 756 amino acids, and lmo2467 encodes a predicted chitin binding protein of 478 amino acids (26). Chromosomal deletion mutants were constructed for each gene indicated in black. Surrounding coding regions are represented by white arrows. (B) Chitinase activity detected in supernatants derived from wild-type, ΔchiA, ΔchiB, and Δlmo2467 strains. Bacterial cultures were grown for 48 h at 30°C in LB broth. Bacterial supernatants were assayed for secreted chitinase activity using the substrate 4-nitrophenyl N,N′-diacetyl-β-d-chitobioside (14, 25). Chitinase units are expressed as the absorbance at 405 nm times 100 divided by the culture optical density measured at 600 nm (OD₆₀₀). Data shown are representative of two independent experiments.