Sato T, Yamada Y, Saijo S, Hori T, Hirose R, Tanaka N, Sazaki G, Nakajima K, Igarashi N, Tanaka M, Matsuura Y
Department of Life Science, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
Acta Crystallogr D Biol Crystallogr. 2000 Aug;56(Pt 8):1079-83. doi: 10.1107/s0907444900008155.
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.
在10 T的均匀静态磁场中生长了蛋清（HEW）溶菌酶的正交晶体。在10 T下生长的所有晶体的取向均使其晶体学c轴与磁场方向平行，并且与在0 T下生长的晶体相比，其摇摆曲线的半高宽（FWHM）平均值更窄。使用高分辨率垂直型四圆衍射仪在日本筑波光子工厂的BL-10A站进行摇摆宽度测量。使用摇摆曲线的FWHM评估晶体的完美度；通过比较在10 T和0 T下生长的七个晶体的FWHM来检查磁场对晶体质量的影响。在高磁场下生长的晶体中，沿a、b和c轴的反射的FWHM分别降低了23.5%、35.3%和27.8%，其他一般反射的FWHM降低了17.4 - 42.2%。这些结果清楚地表明，10 T的磁场提高了正交溶菌酶晶体的晶体完美度。结果，X射线衍射的最大分辨率从0 T时的1.3 Å提高到10 T时的1.13 Å。磁场还影响晶胞尺寸，a轴和c轴的增量分别为0.2%，b轴的增量为0.1%。这些事实表明，在结晶过程中施加高磁场可能会显著提高具有磁各向异性的蛋白质晶体的衍射能力。
