CRYSTALLIZATION AND PRELIMINARY-X-RAY DIFFRACTION STUDIES ON THE WATER-SOLUBLE FORM OF RAT HEME OXYGENASE-1 IN COMPLEX WITH HEME

The water-soluble portion of rat heme oxygenase-1 which lacks 22 hydro phobic amino-acid residues at the C-terminus was expressed in E. coli and crystallized in the form of a complex with heme by the vapor-diffu sion method using polyethylene glycol 4000 as the precipitant. The cry stals belong to the tetragonal space group P4(1)2(1)2 or P4(3)2(1)2, w ith unit-cell dimensions of a = b = 56.7, c = 186.7 Angstrom. The crys tal contains one heme-heme oxygenase-l complex in an asymmetric unit a nd diffracts X-rays beyond 3.0 Angstrom resolution with a conventional X-ray source.