PRODUCTION OF CRYSTALLIZABLE HUMAN CHYMASE FROM A BACILLUS-SUBTILIS SYSTEM

A Bacillus subtilis strain deficient in seven extracellular proteases was used to produce human mast cell chymase and is a viable expression system for serine proteases and other classes of proteins, Chymase is produced at 0.3-0.5 mg/l and is purified by three chromatography step s, Two crystal forms of PMSF-treated chymase were optimized, The first is C2 with a = 47.94 Angstrom, b = 85.23 Angstrom, 174.18 Angstrom, b eta = 96.74 degrees, and diffracts to at least 2.1 Angstrom, while the second is P21212l, with cell dimensions a = 43.93 Angstrom, b = 58.16 Angstrom, and c = 86.09 Angstrom, and a diffraction Limit of approxim ately 1.9 Angstrom. The first crystal form has either three or four mo lecules/asymmetric unit, while the second has one molecule/asymmetric unit. (C) 1997 Federation of European Biochemical Societies.