离子液体1-丁基-3-甲基咪唑氯代盐对溶菌酶结晶的影响

以亲水性离子液体1-丁基-3-甲基咪唑氯盐(BmimCl)为添加剂，研究离子液体对溶菌酶结晶的影响.分别考察了离子液体对溶菌酶晶体数量与尺寸、晶体形貌及蛋白质纯度的影响，并探讨了离子液体对结晶过程影响的作用机制.离子液体通过增大溶菌酶的溶解度和其自身低蒸气压两种途径，降低了溶菌酶在结晶过程中的过饱和度，更有利于晶体的成核和生长,得到更好的结果.如避免多晶态现象的发生，增大晶体的尺寸，降低溶菌酶样品纯度的要求.X-射线衍射分析表明，离子液体未改变晶体的晶型结构，但可提高晶体的衍射分辨率.

The Effects of Ionic Liquid 1-buty-3-methyl-imidazolium Chloride on Lysozyme Crystallization

The crystallization of lysozyme with hydrophilic ionic liquid 1-buty-3-methyl-imidazolium chloride (BmimCl) as an additive was investigated. We discussed the effects of ionic liquid on crystal number, crystal size, crystal morphology, the tolerance to concomitant impurities and the relevant mechanism for protein crystallization in the presence of ionic liquid. The elevated threshold to super-saturation caused by the increased solubility of lysozyme in the presence of BmimCl and the slower super-saturation process of lysozyme induced by the negligible vapor pressure of BmimCl contributed to a lower super-saturation degree, offering a promoted ambient circumstance for nucleation. These eventually offer a prominent promotion to the crystallization of lysozyme, i.e, less crystal polymorphism and precipitation while larger crystals and significantly improved the tolerance to the concomitant impurities. X-ray diffraction analysis showed that the ionic liquid did not change the crystal structure, but it could improve the resolution ratio of the crystal.