Crystallization and preliminary X-ray diffraction studies of polyketide synthase-1 (PKS-1) from Cannabis sativa.

Polyketide synthase-1 (PKS-1) is a novel type III polyketide synthase that catalyzes the biosynthesis of hexanoyl triacetic acid lactone in Cannabis sativa (Mexican strain). PKS-1 was overproduced in Escherichia coli, purified and finally crystallized in two different space groups. The crystal obtained in 0.1 M HEPES buffer pH 7.5 containing 0.2 M calcium acetate and 20%(w/v) polyethylene glycol 3350 diffracted to 1.65 A resolution and belonged to space group P1, with unit-cell parameters a = 54.3, b = 59.3, c = 62.6 A, alpha = 69, beta = 81, gamma = 80 degrees. Another crystal obtained in 0.1 M HEPES buffer pH 7.5 containing 0.2 M sodium chloride and 20%(w/v) polyethylene glycol 3350 diffracted to 1.55 A resolution and belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 54.3, b = 110, c = 130 A. These data will enable us to determine the crystal structure of PKS-1.