1.2.1.77 E257Q-NADP+ mutant at 1.4 A resolution, C296A-NADP+ at 1.4 A resolution, E167A mutant at 1.6 A resolution, E496A mutant at 1.65 A resolution 1.2.1.77 sitting drop vapour diffusion method, at 18°C in 29% PEG 3350K and 100 mM bis-Tris (pH 6.0), 1.6 A crystal structure of ALDHC in complex with NADPH bound in the cofactor-binding pocket and an ordered fragment of a polyethylene glycol molecule bound in the substrate tunnel