Crystallization behaviour of glyceraldehyde dehydrogenase from Thermoplasma acidophilum.

The glyceraldehyde dehydrogenase from Thermoplasma acidophilum (TaAlDH) is a microbial enzyme that catalyzes the oxidation of D-glyceraldehyde to D-glycerate in the artificial enzyme cascade designed for the conversion of glucose to the organic solvents isobutanol and ethanol. Various mutants of TaAlDH were constructed by a random approach followed by site-directed and saturation mutagenesis in order to improve the properties of the enzyme that are essential for its functioning within the cascade. Two enzyme variants, wild-type TaAlDH (TaAlDHwt) and an F34M+S405N variant (TaAlDH F34M+S405N), were successfully crystallized. Crystals of TaAlDHwt belonged to the monoclinic space group P1211 with eight molecules per asymmetric unit and diffracted to a resolution of 1.95 Å. TaAlDH F34M+S405N crystallized in two different space groups: triclinic P1 with 16 molecules per asymmetric unit and monoclinic C121 with four molecules per asymmetric unit. These crystals diffracted to resolutions of 2.14 and 2.10 Å for the P1 and C121 crystals, respectively.