T. Sato et al., Enhancement in the perfection of orthorhombic lysozyme crystals grown in ahigh magnetic field (10 T), ACT CRYST D, 56, 2000, pp. 1079-1083
Orthorhombic crystals of hen egg-white (HEW) lysozyme were grown in a homog
eneous and static magnetic field of 10 T. All crystals grown at 10 T were o
riented such that their crystallographic c axes were parallel to the magnet
ic field direction and showed a narrower average full-width at half-maximum
(FWHM) of the rocking curve than those grown at 0 T. Rocking-width measure
ments were made at the BL-10A station at the Photon Factory, Tsukuba, Japan
, using a high-resolution vertical-type four-circle diffractometer. Crystal
perfection was evaluated using the FWHM of the rocking curve; the effects
of the magnetic field on the quality of the crystals were examined by compa
rison of the FWHM of seven crystals grown at 10 and 0 T. The FWHMs of the r
eflections along the a, b and c axes decreased by 23.5, 35.3 and 27.8%, res
pectively, and those of other general reflections decreased by 17.4-42.2% i
n the crystals grown at high magnetic field. These results clearly showed t
hat a magnetic field of 10 T improved the crystal perfection of the orthorh
ombic lysozyme crystals. As a result, the maximum resolution of X-ray diffr
action increased from 1.3 Angstrom at 0 T to 1.13 Angstrom at 10 T. The mag
netic field also affected the dimensions of the unit cell, increments being
0.2% for the a and c axes and 0.1% for the b axis, respectively. These fac
ts suggest that the application of a high magnetic field during crystalliza
tion might result in remarkable enhancements in the diffraction power of pr
otein crystals having magnetic anisotropy.