Improvement in diffraction maxima in orthorhombic HEWL crystal grown under high magnetic field

Orthorhombic crystals of hen egg-white lysozyme (HEWL) were grown under a homogeneous magnetic field of 10 T (B = 10 T) In the magnetic field, crystals were oriented such that their crystallographic c-axes were parallel to the magnetic field, and gave narrower average rocking widths than those grown under 0 T. Crystal quality was evaluated using the full-width at half-maximum (FWHM) of the rocking curve, and the effects of a magnetic field were examined by comparing FWHM of seven crystals grown at 10 T with an equal number grown at OT. FWHM values in (1000), (080), and (006) reflections decreased by 25%, 38%, and 32%, respectively, and those of general reflections decreased by 7-45% in crystals grown under high magnetic field. These results show that a magnetic field of 10 T improved the crystal perfection of the orthorhombic lysozyme crystals. At the same time, the maximum resolution limit of X-ray diffraction increased from 1.33 A for 0 T to 1.13 A for 10 T. These facts suggest that the application of magnetic field for crystallization might generally have a striking effect in enhancing the diffraction power of protein crystals.