FIG 8.

Arginine- and lysine-specific gingipain activity in whole cells or cell-free supernatants. P. gingivalis washed cells (WC) or the corresponding spent growth medium (CF) was assayed for either arginine-specific or lysine-specific gingipain activity using synthetic chromogenic substrates, as described in Materials and Methods. Cultures were adjusted to the same optical densities, and pelleted bacteria were resuspended to a volume equal to that of the adjusted culture to allow a direct assessment of the amount of secreted versus cell-associated activity. Gingipain activity in the Δ77bpIR mutant is reduced compared to that in the parent strain W83. Error bars represent standard deviations of technical replicates.