Crystallization and preliminary X-ray crystallographic analysis of the human type 3 3 alpha-hydroxysteroid dehydrogenase at 1.8 A resolution.

In androgen-sensitive target tissues, 3 alpha-hydroxysteroid dehydrogenase regulates the androgen receptor (AR) activity by catalyzing the inactivation of 5 alpha-dihydrotestosterone (the most natural potent androgen) to 5 alpha-androstane-3 alpha,17 beta-diol. In this report, the crystallization of a human prostatic type 3 3 alpha-hydroxysteroid dehydrogenase, a member of the aldo-keto reductase superfamily, is described. Two different crystal forms of the complex between the human type 3 3 alpha-HSD, NADP(+) and testosterone have been obtained using PEG as precipitant. Crystal form I, which diffracts to 1.6 A, belongs to the monoclinic space group P2(1), with unit-cell parameters a = 55.07, b = 87.15, c = 76.88 A, beta = 107.37 degrees and two subunits in the asymmetric unit. A complete data set has been collected at 1.8 A. Crystal form II, which diffracts to 2.6 A, belongs to the rhombohedral space group R32, with unit-cell parameters a = b = 143.59, c = 205.86 A, alpha = beta = 90, gamma = 120 degrees and two subunits in the asymmetric unit.