Crystallization and preliminary X-ray analysis of aspartate racemase from Pyrococcus horikoshii OT3

Aspartate racemase from Pyrococcus horikoshii OT3 (P. AspR) has been crystallized in three crystal forms by the sitting-drop vapour-diffusion method. The crystals belong to the space groups P21, P212121 and P3121 (or P3221). The crystals of space group P21 diffract X-rays beyond 1.7 A resolution under 90 K liquid-nitrogen cryoconditions with synchrotron radiation and were selected for structure determination. Two heavy-atom derivatives of this crystal form were obtained by the soaking method, which afforded the initial electron-density map.