Fig. 4.

Fixation of AtxA complexes with a cysteine-reactive cross-linking agent. Cultures of the atxA-null strain UT376 containing pUTE658 (encoding AtxA) or pUTE991 (encoding AtxA-His) were induced with 40 μM IPTG. Cell lysates or affinity-purified AtxA-His were treated with the cross-linking agent BMH. SDS-PAGE (4-15%) and Western blots with AtxA-specific antibody were used to detect various forms of AtxA. EV = empty vector, L = cell lysate, and AP = affinity-purified. Molecular weights of the protein standards are listed (SeeBlue Plus2, Invitrogen).