Crystallization and preliminary X-ray analysis of the GST-fused human Bri3 N-terminal domain

Bri3 is a recently identified proline-rich transmembrane polypeptide up-regulated during TNF-mediated inflammation and immunity. The polyproline-rich N-terminal (residues 1-60) domain of Bri3 was affinity-purified to homogeneity as a glutathione-S-transferase (GST) fusion protein. Crystals were obtained in approximately 3 d by the equilibrium vapour-diffusion method from a solution containing 1.5-2.2 M ammonium sulfate and 0.1 M bis-tris pH 6.0. The crystals belong to space group P4(3)2(1)2, with unit-cell parameters a = b = 91.66, c = 57.53 A. An X-ray data set was collected to 1.6 A resolution using synchrotron radiation, with an Rsym of 0.058 and a completeness of 95.3%. There is one molecule of the fusion protein in the asymmetric unit, which corresponds to approximately 35% solvent content.