Description
Most of O157 E Coli strains produce potent toxin like Shiga toxin, causing haemorrhagic colitis and haemolytic ureamic syndrome. There are two Shiga like toxin, Shiga-like toxin 1 and 2. Shiga-like toxin 1 can be neutralized by antibody against Shiga toxin, while Shiga-like toxin 2 can not neutralized by this antibody. Each of them is composed by A and B peptide chains, chain A plays a role in the inhibiting of protein synthesis, and chain B has effect to binding to receptor. A functional region of Shiga-like toxin 2 subunit B (22-87 amino acids, Swiss-Prot # Q47646) responsible for receptor binding, was expressed and purified, a 6xhis tag was attached its N-terminus. Recombinant SLT 2B mimics its native protein forming dimer or trimer on SDS-PAGE gel under denature condition. Nature SLT-1B forms pentamer protein