Purification and characterization of a Corynebacterium ulcerans bacteriocin (ulceracin 378)

Corynebacterium ulcerans strain 378 produces a bacteriocin (ulceracin 378) and a toxin when grown on semi-solid medium. Ulceracin 378 was purified 360-fold by dialysis and chromatography on DEAE-cellulose and Sephadex G-200. On the basis of Ultrogel AcA22 gel filtration its molecular weight was about 900 000. It could be dissociated by 2-mercaptoethanol and sodium dodecyl sulphate into smaller subunits of 25 000. The bactericidal activity was associated with this subunit which contained no carbohydrate or lipid. Ulceracin 378 was thermostable and stable over a wide pH range. Purified ulceracin 378 did not have a toxic effect (lethal) on guinea-pigs and rabbits and was immunologically distinct from the toxin.