Isolation and characterization of syringacin W-1, a bacteriocin produced by <i>Pseudomonas syringae</i> pv. <i>syringae</i>

Abstract

Syringacin W-1, a bacteriocin produced by Pseudomonas syringae pathovar syringae strain PsW-1, is a 20 × 75 nm rod-shaped particle composed of an inner core and outer sheath. Production of syringacin W-1 in broth was induced with 0.1 μLg/mL mitomycin C. The bacteriocin was purified from culture lysates using ultrafiltration, rate zonal centrifugation in sucrose gradients, and DEAE-cellulose chromatography. Purity was evaluated by subjecting syringacin W-1 preparations to electrophoresis in polyacrylamide gels under nondenaturing and denaturing conditions. The chemical composition was principally protein (67.2%), and also comigrating nonessential carbohydrate (10–35%). The physical properties of purified syringacin W-1 were a sedimentation coefficient of 104 for rod-shaped particles, pH stability of 5.2–8.2, and temperature stability from −20 to 40 °C. The bacteriocin was resistant to proteases and to 12 of 13 surfactants tested.