Enhancement in the perfection of orthorhombic lysozyme crystals grown in a high magnetic field (10 T)

Abstract

Orthorhombic crystals of hen egg-white (HEW) lysozyme were grown in a homogeneous and static magnetic field of 10 T. All crystals grown at 10 T were oriented such that their crystallographic c axes were parallel to the magnetic 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 measurements 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 comparison of the FWHM of seven crystals grown at 10 and 0 T. The FWHMs of the reflections along the a, b and c axes decreased by 23.5, 35.3 and 27.8%, respectively, and those of other general reflections decreased by 17.4-42.2% in the crystals grown at high magnetic field. These results clearly showed that a magnetic field of 10 T improved the crystal perfection of the orthorhombic lysozyme crystals. As a result, the maximum resolution of X-ray diffraction increased from 1.3 A at 0 T to 1.13 A at 10 T. The magnetic 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 facts suggest that the application of a high magnetic field during crystallization might result in remarkable enhancements in the diffraction power of protein crystals having magnetic anisotropy.

Effects of Strong Magnetic Fields on Natural Convection in the Vicinity of a Growing Cubic Protein Crystal

“…The simulation results explain the experimental results: when crystals were formed under various effective gravity, the higher quality crystals were obtained with decreasing effective gravity as shown in Fig. 2. 7) The simulation also agrees with the improvements of crystal quality 7,8) and the decrease of crystal growth rate 9,10) when crystals were formed in a uniform field.…”

“…In the present paper, in order to explain the observed phenomena, [7][8][9][10] we numerically studied the damping of natural convection in the vicinity of a growing protein crystal, considering the effects of a vertical magnetization force, a magnetically induced increase of viscosity and Lorentz force.…”

Technique for High-Quality Protein Crystal Growth by Control of Subgrain Formation under an External Electric Field

“…However, the growth of high-quality single crystals of proteins is difficult, which is an impediment to accurate elucidation of the 3D structures of protein molecules. Therefore, the establishment of crystallization techniques to obtain high-quality single crystals of proteins has been intensively pursued using magnetic fields [1][2][3][4][5][6][7][8], microgravity [9][10][11][12][13][14][15][16], electric fields [17][18][19][20][21], solution flow [22][23][24][25] and gel as a growth host media [26][27][28][29][30][31][32]. In this article, the improvement of the crystal quality of tetragonal hen egg white (HEW) lysozyme crystals as a model protein is demonstrated by applying an external electric field.…”

Effect of an External Electric Field on the Kinetics of Dislocation-Free Growth of Tetragonal Hen Egg White Lysozyme Crystals

“…The growth of high-quality single crystals of proteins has been intensively pursued using magnetic fields [3][4][5][6][7][8][9], microgravity [10][11][12][13][14][15][16], solution flow [17][18][19][20], and gel as a growth host media [21][22][23][24][25][26][27][28]. A growth technique mediated by screw dislocations under low supersaturation has also been proposed [29][30][31][32].…”