Crystallization and preliminarycrystallographic analysis of a zincdependent alcohol dehydrogenase from Streptococcus pneumoniae

Alcohol dehydrogenase (ADH) is one of essential enzymes for all living organisms, and conserved from archaea to mammals. The most abundant type of ADH is zinc-containing one. All the zinc containing ADHs possess the catalytic zinc site, while some have the second, structural zinc site. ADHs require either NAD(H) or NADP(H) as a cofactor. Despite lots of efforts to determine the key residues for cofactor specificity of ADHs, there is no general rule for cofactor specificity so far. To establish the general rules for the cofactor specificity of ADHs by structural analysis, we cloned and overexpressed the zinc dependent alcohol dehydrogenase from Streptococcus pneumoniae strain D39 (SpADH2) in Escherichia coli. Rod-shape crystals of SpADH2 were obtained by hanging-drop vapour diffusion from a reservoir solution containing 50 mM Tris-HCl pH 8.0, 50 mM NaCl, PEG 3350 15% (w/v) and diffracted to 2.19 Å resolution. Crystal belonged to orthorhombic space group P212121 with unit cell parameters a = 88.2 Å, b = 123.2 Å, c = 130.4 Å and contained four molecules in the asymmetric unit.