Preliminary crystallographic data for stearoyl-acyl carrier protein desaturase from castor seed.

Recombinant stearoyl-acyl carrier protein desaturase (EC 1.14.99.6) from castor seed has been crystallized with polyethylene glycol 8000 as precipitant. The crystals are orthorhombic, space group P2(1)2(1)2(1) with cell dimensions a = 81.3, b = 146.4 and c = 197.7 A. The observed diffraction pattern extends to at least 2.5 A resolution. Rotation function calculations indicate a non-crystallographic 3-fold rotation axis parallel to the crystallographic a-axis. Perpendicular to this axis, 2-fold rotation axes were found at 30 degrees intervals, i.e. maxima at kappa = 180 degrees, phi = 90 degrees and omega = 30 degrees and 60 degrees, respectively. Together with the packing density of the crystals (Vm = 2.4 A3/Da for n = 6), these results suggest, that the crystal asymmetric unit most likely contains a hexamer of desaturase subunits.