Crystallization and preliminary X-ray diffraction studies of monomeric isocitrate dehydrogenase from Corynebacterium glutamicum

A monomeric isocitrate dehydrogenase has been crystallized for the first time. This enzyme catalyzes the conversion of isocitrate to oxalosuccinate and subsequently to α-ketoglutarate and CO₂; the coenzyme NADP⁺ is reduced to NADPH during the reaction. Polyethylene glycol 2000 monomethyl ether was used to crystallize the enzyme in space group C2 with unit-cell parameters a = 137.1, b = 54.6, c = 126.4 Å, β = 108.2°. The very small crystal (0.05 × 0.20 × 0.05 mm) diffracted to 3.5 Å d spacing using synchrotron radiation.