CRYSTALLIZATION AND PRELIMINARY-X-RAY ANALYSIS OF A THIOL-ACTIVATED CYTOLYSIN

We present the first reported crystallization of a member of the thiol -activated family of protein toxins. Perfringolysin O, a virulence fac tor of Clostridium perfringens, has been crystallized in two different forms by the hanging drop vapor diffusion method. In one form the tox in crystallizes with PEG 20000 in the orthorhombic space group C222(1) with cell dimensions of a = 47.8 Angstrom, b = 182.0 Angstrom and c = 175.5 Angstrom and the crystals diffract to beyond 2.5 Angstrom resol ution, In the second form the toxin crystallizes in a large variety of organic solvents including malt whisky. This crystal form belongs to the orthorhombic space group P222(1) with unit cell dimensions a = 47. 1 Angstrom, b = 166.1 Angstrom and c = 214.0 Angstrom and with diffrac tion observed to 2.4 Angstrom resolution.