Crystallization and preliminary X-ray diffraction analysis of the complex of human placental 17 beta-hydroxysteroid...

Single crystals of human placental 17 beta-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 A, b = 45.03 A, c = 61.29 A, and beta = 99.1 degrees. A complete set of diffraction data to 2.9 A has been collected on native crystals.