Crystallization and initial X-ray diffraction analysis of human pyruvate dehydrogenase

Human pyruvate dehydrogenase (E1) is a component enzyme of the pyruvate dehydrogenase complex. The enzyme catalyzes the irreversible decarboxylation of pyruvic acid and the rate-limiting reductive acetylation of the lipoyl moiety linked to the dihydrolipoamide acetyltransferase component of the pyruvate dehydrogenase complex. E1 is an α₂β₂ tetramer (∼154 kDa). Crystals of this recombinant enzyme have been grown in polyethylene glycol 3350 using a vapor-diffusion method at 295 K. The crystals are characterized as orthorhombic, space group P2₁2₁2₁, with unit-cell parameters a = 64.2, b = 126.9, c = 190.2 Å. Crystals diffracted to a minimum d spacing of 2.5 Å. The asymmetric unit contains one α₂β₂ tetrameric E1 assembly; self-rotation function analysis showed a pseudo-twofold symmetry relating the two αβ dimers.