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.