EtxB expressed as a fusion protein with GlyGly-CTERM.

Cultures of WT and rssP::kan mutant strains expressing EtxB or EtxB-GlyGly-CTERM were grown overnight in LB broth with 100 μg/mL carbenicillin and 50 μM IPTG. Cells (C) and culture supernatants (S) were subjected to SDS-PAGE and immunoblotting with monoclonal anti-EtxB. The positions of intact EtxB-GlyGly-CTERM (arrowhead) and EtxB and processed EtxB-GlyGly-CTERM (arrow) are indicated on the right.