Expression, crystallization and preliminary X-ray diffraction studies of recombinant Clostridium perfringens beta 2-toxin.

Clostridium perfringens is a Gram-positive sporulating anaerobic bacterium that is responsible for a wide spectrum of diseases in animals, birds and humans. The virulence of C. perfringens is associated with the production of several enterotoxins and exotoxins. beta2-toxin is a 28 kDa exotoxin produced by C. perfringens. It is implicated in necrotic enteritis in animals and humans, a disease characterized by a sudden acute onset with lethal hemorrhagic mucosal ulceration. The recombinant expression, purification and crystallization of beta2-toxin using the batch-under-oil technique are reported here. Native X-ray diffraction data were obtained to 2.9 A resolution on a synchrotron beamline at the F2 station at Cornell High Energy Synchrotron Source (CHESS) using an ADSC Quantum-210 CCD detector. The crystals belong to space group R3, with a dimer in the asymmetric unit; the unit-cell parameters are a = b = 103.71, c = 193.48 A, alpha = beta = 90, gamma = 120 degrees using the hexagonal axis setting. A self-rotation function shows that the two molecules are related by a noncrystallographic twofold axis with polar angles omega = 90.0, phi = 210.3 degrees.