FIG. 8.
Effect of an invB mutation on the stability of SopE, SopEM45, and SopE2M45. SB161 (ΔinvG) and M590 (ΔinvG invB::aphT) or the same strains carrying pM136 (B), pM226 (C), pM416 (D), or pM417 (E) were expressed under secretion-inducing conditions (see Materials and Methods). After 4 h of subculturing 100-μl aliquots were removed (zero time), and chloramphenicol was added to the remaining cultures. One-hundred-microliter aliquots were removed after 5, 10, 20, and 40 min and separated by SDS-PAGE, and the protein levels were analyzed by Western blotting by using an anti-SopE (α-SopE) antiserum (A) and a monoclonal anti-M45 (α-M45) antibody (B to E). The blots were reprobed by using an anti-OmpC (α-OmpC) antibody to control the amount of protein loaded.