MobMN243 ligand-dependent proteolysis as analyzed by 12% SDS-PAGE. Lane 1, full-length MobM (57.9 kDa), incubated for 2 months at 4°C. Lane 2, MobMN243 (28.4 kDa), fresh sample. Lane 3, MobMN243 incubated for 2 months at 4°C. Lane 4, MobMN243, incubated for 2 months at 4°C in the presence of MnCl2 (15 mM final concentration). Lane 5, MobMN243 incubated for 2 months at 4°C in the presence of IR1+8 (180 μM). Lane 6, MobMN243 incubated for 2 months at 4°C in the presence of MnCl2 plus IR1+8. Lane 7, MobMN199 (23.1 kDa), nondegraded fresh sample, included for comparison to the degraded samples in lanes 1 to 6. The marker lane (M) was loaded with SeeBlue prestained standards (Invitrogen).