Growth of High Quality Protein Crystals using Magnetic Field

以鸡蛋清溶菌酶为模型蛋白，研究了磁场对溶菌酶结晶的影响。主要研究结果如下：1.晶体的磁取向除了磁场强度外，还可以通过改变结晶容器的生长速率和深度来控制蛋白质晶体的磁取向.晶体的生长速率在11 T下对蛋白质晶体生长的原位观察表明，磁场降低了晶体的生长速率. NaCl水溶液中对流的阻尼对NaCl水溶液中温度驱动的对流的原位观察表明，即使在“水溶液”的情况下，磁场也会阻尼对流.晶体质量的改善10 T下生长的正交晶系溶菌酶晶体的摇摆曲线测量表明，磁场大大提高了蛋白质单晶的“晶体完整性”。具有较高的衍射极限和较小的X射线辐射损伤.其他外力的影响I：高压随着静水压力的增加，四方溶菌酶晶体的溶解度增加，而正交溶菌酶晶体的溶解度降低。表面能的增加降低了四方晶和斜方晶的生长速率.二、其他外力的影响：微重力利用落物装置进行的微重力实验表明：1）Grashoff数可以很好地预测浮力对流; 2）由于界面污染，水-气界面的Marangoni对流在10-15 min内下降到10%以下。

We chose hen egg-white lysozyme as a model protein, and studied a magnetic field effects on the crystallization of lysozyme crystals. Main results obtained are summarized as follows.1. Magnetic orientation of the crystalsMagnetic orientation of protein crystals could be controlled by changing the growth rate and depth of the crystallization container in addition to the magnetic field strength.2. Growth rate of the crystalsIn situ observation of growing protein crystals under 11T revealed that a magnetic field decreased the growth rate of the crystals.3. Damping of convection in NaCl aqueous solutionIn situ observation of temperature-driven convection in NaCl aqueous solution showed that a magnetic field damped the convection even in the case of "aqueous solution".4. Improvement of the quality of the crystalRocking curve measurement of orthorhombic lysozyme crystals grown under 10T revealed that a magnetic field drastically increased the "crystal perfection" of protein single crystal., and gave higher diffraction limit and smaller X-ray radiation damage.5. Effects of other external force I : high pressureWith an increase in hydrostatic pressure, solubility of tetragonal lysozyme crystals increased, though that of orthorhombic one decreased. Increase in surface energy decreased the growth rate of tetragonal and orthorhombic crystals.6. Effects of other external force II : microgravityMicrogravity experiments using dropping facility revealed that 1) Grashoff number could be a good measure to predict buoyancy convection, and that 2) Marangoni convection at water-air interface decreased to less than 10% within 10-15 min because of the contamination of the interface.