Crystallization and preliminary X-ray crystallographic analysis of the human type 3 3α-hydroxysteroid dehydrogenase at 1.8 Å resolution

In androgen‐sensitive target tissues, 3α‐hydroxysteroid dehydrogenase regulates the androgen receptor (AR) activity by catalyzing the inactivation of 5α‐dihydrotestosterone (the most natural potent androgen) to 5α‐androstane‐3α,17β‐diol. In this report, the crystallization of a human prostatic type 3 3α‐hydroxysteroid dehydrogenase, a member of the aldo–keto reductase superfamily, is described. Two different crystal forms of the complex between the human type 3 3α‐HSD, NADP+ and testosterone have been obtained using PEG as precipitant. Crystal form I, which diffracts to 1.6 Å, belongs to the monoclinic space group P21, with unit‐cell parameters a = 55.07, b = 87.15, c = 76.88 Å, β = 107.37° and two subunits in the asymmetric unit. A complete data set has been collected at 1.8 Å. Crystal form II, which diffracts to 2.6 Å, belongs to the rhombohedral space group R32, with unit‐cell parameters a = b = 143.59, c = 205.86 Å, α = β = 90, γ = 120° and two subunits in the asymmetric unit.