Crystals for Chimera 3 and Chimera 4 were grown by hanging drop vapor diffusion at 4 ºC using 10-15 mg/mL protein and a precipitant solution of 0.1 M tris hydrochloride pH 6.5-8.5, 0.2 M magnesium acetate tetrahydrate, and 20-25 % PEG 8000 at a 2:2:0.5 protein:well:20% benzamidine hydrochloride drop ratio. Both the tungstate and vanadate bound structures were obtained by adding either 3.9 mM sodium tungstate (Na2WO4) or 1 mM sodium metavanadate (Na3VO4) to the protein for co-crystallization. Crystals grew in 24 hours and were transferred to a cryo-protectant solution containing mother liquor, 20% benzamidine hydrochloride, and 50% sucrose before flash freezing in liquid nitrogen.