Crystallization and preliminary X-ray analysis of aldehyde dehydrogenase from Vibrio harveyi

Abstract

Aldehyde dehydrogenase from Vibrio harveyi catalyzes the oxidation of long-chain aliphatic aldehydes to acids. The enzyme is unique among the family of aldehyde dehydrogenases in that it exhibits much higher specificity for the cofactor NADP+ than for NAD+. The sequence of this form of the enzyme varies significantly from the NAD+ dependent forms, suggesting differences in the three-dimensional structure that may be correlated to cofactor specificity. Crystals of the enzyme have been grown both in the presence and absence of NADP+ using the hanging drop vapor diffusion technique. In order to improve crystal size and quality, iterative seeding techniques were employed. The crystals belong to space group P21, with unit cell dimensions a = 79.4 Å, b = 131.1 Å, c = 92.2 Å, and β = 92.4°. Freezing the crystal to 100 K has enabled a complete set of data to be collected using a rotating anode source (λ = 1.5418 Å). The crystals diffract to a minimum d-spacing of 2.6 Å resolution. Based on density calculations, two homodimers of molecular weight 110 kDa are estimated to be present in the asymmetric unit. Self-rotation functions show the presence of 3 noncrystallographic twofold symmetry axes.