Fig. 7.

ArgT was degraded by HtrA protease in vivo and in vitro. A, ArgT could not be degraded in the htrA deletion mutant. Plasmid pProEX-HTb-argT was transformed into 2457T and 2457TΔhtrA, and then strains carrying the recombinant plasmids were induced by IPTG at 37 and 30 °C, respectively. B, 50 μg of GST-ArgT and 0.5 μg of GST-HtrA/HtrAS210A fusion proteins were incubated in a final volume of 100 μl of 50 mm Tris-Cl, pH 8.0 buffer at 37 and 30 °C. 15 μl of the incubation was removed every hour and loaded for SDS-PAGE. M, protein marker (Fermentas).