CRYSTALLIZATION AND CRYSTAL PACKING OF RECOMBINANT-3 (OR RECOMBINANT-17) BETA-HYDROXYSTEROID DEHYDROGENASE FROM COMAMONAS-TESTOSTERONI ATTC-11996

The enzyme 3 (or 17) beta-hydroxysteroid dehydrogenase from Comamonas testosteroni was crystallized. Crystals, of up to 0.6 mm in their long est dimension and suitable for a crystallographic analysis have been o btained by the vapour diffusion method. They belong to the orthorhombi c lattice type and diffract to a maximum resolution of 0.23 nm. A fina l data set obtained by merging data from three crystals resulted in a completeness of 90% with an R(merge) of 6%. A molecular replacement se arch carried out by using 3 alpha (or 20 beta)-hydroxysteroid dehydrog enase from Streptomyces hydrogenans as a search model allowed us to as sign I222 as the correct space group and to propose a model for the cr ystal packing, with one monomer per asymmetric unit. Thus, the whole u nit cell contains two tetramers. The R-factor after rigid body refinem ent is 48.1%.