Preliminary X-ray crystallographic studies on alcohol dehydrogenase from Drosophila

The alcohol dehydrogenase (ADHase) enzyme catalyses the oxidation of alcohols to aldehydes or ketones using NAD+ as a cofactor. Functional ADHase from Drosophila lebanonensis is a dimer, with a monomeric molecular weight of 27,000 and with 254 residues in each polypeptide chain. Crystals of the protein have been grown with and without NAD+. Two crystal forms have been observed. Most crystals are plate-like, 0·05 mm in their shortest dimension and up to 0·4 mm in their longest dimension. These crystals are generally too small to diffract efficiently using conventional X-ray sources, so preliminary studies were carried out using the Synchrotron Radiation Source at the SERC Daresbury Laboratory. Twinning was a severe problem with this crystal form. The second form is grown in the absence of NAD+ but with dl-dithiothreitol present. These crystals grow more evenly and diffract to better than 2 Å resolution. They are monoclinic, with cell dimensions. a = 81·24(6) Å, b = 55·75(4) Å, c = 109·60(7) Å and β = 94·26(9) °, space group P21. There are two dimers in the asymmetric unit, but at low resolution a rotated cell with one dimer per asymmetric unit can be obtained.