Preliminary crystallographic studies of urease from jack bean and from Klebsiella aerogenes

Ureases from both jack bean ( Canavalia ensiformis) seeds and Klebsiella aerogenes have been crystallized by the hanging drop method. The plant-derived urease crystals are regular octahedra analogous to those obtained by Sumner. Preliminary X-ray diffraction studies show that the crystals belong to the cubic space group F4 132, with a = 364 A ̊ , and appear to contain one or two subunits in the asymmetric unit. Using a synchrotron source, the crystals diffract to near 3·5 Å resolution. Crystals of urease from K. aerogenes belong to the cubic space group I23 or I2 13, with a = 170·8 A ̊ and appear to contain a single catalytic unit per asymmetric unit. The crystals diffract to better than 2·0 Å resolution and are well suited for structural analysis.