A method for the purification of Shiga-like toxin 1 subunit B using a commercially available galabiose–agarose resin

We describe a procedure for the affinity purification of Shiga toxin 1 subunit B (SLTB) using a commercial galabiose–agarose resin. Recombinant SLTB was purified to 99% homogeneity in a single-step protocol, from the periplasmic extracts of Vibrio cholerae 0395 N1/pSBC54. SDS–PAGE of the affinity purified SLTB showed one band of 8 kDa MW. SLTB purified by this procedure retained its chemical and biological activity as demonstrated by re-binding to the galabiose–agarose resin, and receptor-mediated binding and uptake in Vero cells. The galabiose–agarose resin could isolate roughly 1 mg of SLTB/mL of gel. The resin was stable over 3 years and 500 cycles/year of usage. Hence, this method is a straightforward approach to the large-scale preparation of SLTB at a reasonable cost.