Recombinant bovine uteroglobin at 1.6 A resolution: a preliminary X-ray crystallographic analysis

Uteroglobin (UG) is a conserved protein which is induced by progesterone and secreted by the epithelia of various mammalian reproductive and respiratory organs. Recombinant bovine uteroglobin (recbUG), consisting of 80 amino acids with a C-terminal His6 tag, was overexpressed in Escherichia coli and purified. The protein was crystallized in two geometric forms, rhomboid and cuneate (wedge-shaped), by the hanging-drop vapour-diffusion method at 295 K. The rhomboid crystals diffracted to a maximum resolution of 1.6 A using synchrotron radiation. These crystals belong to space group P2(1)2(1)2, with unit-cell parameters a = 81.42, b = 82.82, c = 45.26 A, and contain four monomers per asymmetric unit. The cuneate crystals diffracted to 2.35 A resolution using a rotating-anode generator. These crystals belong to space group C222(1), with unit-cell parameters a = 43.39, b = 93.94, c = 77.30 A, and contain two molecules per asymmetric unit.