Crystallization and structural analysis of GADPH from Spinacia oleracea in a new form

Two crystalline forms of GADPH (d-glyceraldehyde-3-phosphate dehydrogenase) from Spinacia oleracea were obtained using sitting-drop vapor diffusion. Despite the very low concentration of GADPH in the solutions, two crystalline forms were obtained, one of which was the previously reported C222 space group with unit-cell parameters a = 155.3, b = 181.7, c = 107.6 Å and the other of which belonged to a new space group I4₁22, with unit-cell parameters a = b = 120.9, c = 154.5 Å. Diffraction data were measured from both native and derivatives, yielding structures at a resolution limit of 3.0 Å. Differences at the NAD⁺/NADP⁺-binding site seen in these structures compared with the previously reported structure with bound coenzyme suggest that conformational changes associated with pyridine-nucleotide binding may play a role in the regulation of this enzyme.