Crystallization and preliminary X-ray diffraction analysis of the complex of human placental 17β-hydroxysteroid dehydrogenase with NADP⁺

Single crystals of human placental 17β-hydroxysteroid dehydrogenase: an enzyme that plays an important role in the interconversion of estrogens, were obtained as the NADP⁺ complex. These are the first crystals suitable for complete X-ray structure analysis ever reported for a steroid-converting enzyme from a human source. The crystals were grown by vapor diffusion at pH 7.5 with polyethyleneglycol (4000) as the precipitating agent. They have a monoclinic space group C2 and unit cell parameters are a = 123.03 Å, b = 45.03 Å, c = 61.29 Å, and β = 99.1°. A complete set of diffraction data to 2.9 Å has been collected on native crystals.