Crystallization and preliminary X-ray diffraction studies of a deglycosylated glucose oxidase from Penicillium amagasakiense.

Abstract The dimeric glucose oxidase from Penicillium amagasakiense was deglycosylated, purified and crystallized as a complex with its coenzyme FAD. Deglycosylation and purification to isoelectric homogeneity were shown to be an important prerequisite step to obtain crystals suitable for X-ray investigations. Crystals of the deglycosylated enzyme were reproducibly grown using ammonium sulfate as precipitant at pH 7.4 to 7.5. Crystals diffract to at least 2.0 A resolution and belong to the orthorhombic space group P 2 1 2 1 2 1 , with refined lattice constants of a = 59.3 A , b = 136.3 A and c = 156.7 A . Assuming two monomers (≈ 135 kDa) per asymmetric unit the V m value is 2.3 A 3 /Da.