Purification, crystallization and preliminary X-ray study of orotidine 5 '-monophosphate decarboxylase

Orotidine-5'-monophosphate decarboxylase (ODCase) from Methanobacterium the rmoautotrophicum has been crystallized with and without the inhibitor 6-aza UMP by the vapour-diffusion method. In the absence of the inhibitor, the pr otein crystallizes in space group P4(1)2(1)2 (unit-cell parameters a = b = 56.9, c = 124.5 Angstrom) with one molecule per asymmetric unit; the crysta ls diffract to 1.8 Angstrom resolution. In the presence of the inhibitor, t he protein crystals are monoclinic, space group P2(1) (unit-cell parameters a = 73.0, b = 98.6, c = 73.3 Angstrom, gamma = 104.0 degrees), with four m olecules in the asymmetric unit; the crystals diffract to 1.5 Angstrom reso lution.