Research Center for Analytical Sciences, Northeastern University, Box 332, Shenyang 110819, China.
Analyst. 2010 Sep;135(9):2241-8. doi: 10.1039/c0an00244e. Epub 2010 Jul 8.
The crystallization of lysozyme with hydrophilic ionic liquid 1,3-butylimidazolium chloride (BBimCl) as an additive was investigated with hanging-drop vapor diffusion crystallization protocol. The elevated threshold to super-saturation caused by the increased solubility of lysozyme in the presence of BBimCl and the slower super-saturation process of lysozyme induced by the negligible vapor pressure of BBimCl contributed to a lower super-saturation degree, offering a promoted ambient circumstance for nucleation and providing a controlled velocity for the growth of lysozyme crystal. 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 or sample matrices for the crystallization of lysozyme. Therefore, the presence of BBimCl enables the direct crystallization of lysozyme from a real complex sample matrix, i.e., egg-white, which opens a promising avenue for the development of protein crystallization methodology with ionic liquids as an additive and offers vast potentials for the practical separation/purification of proteins of interest from complex real sample matrices.
采用悬滴蒸汽扩散法，研究了在亲水性离子液体 1-丁基-3-甲基咪唑氯盐（BBimCl）存在下溶菌酶的结晶。由于 BBimCl 增加了溶菌酶的溶解度，导致过饱和度升高的阈值增加，同时由于 BBimCl 的蒸汽压可忽略不计，溶菌酶的过饱和度过程较慢，这有助于降低过饱和度，为成核提供了更好的环境条件，并为溶菌酶晶体的生长提供了可控的速度。这些最终对溶菌酶的结晶起到了显著的促进作用，即减少了晶体的多态性和沉淀，同时获得了更大的晶体，并且显著提高了溶菌酶结晶对伴随杂质或样品基质的耐受性。因此，BBimCl 的存在可以使溶菌酶直接从真实复杂的样品基质（如蛋清）中结晶，这为离子液体作为添加剂的蛋白质结晶方法的发展开辟了广阔的前景，并为从复杂的真实样品基质中实际分离/纯化目标蛋白质提供了巨大的潜力。
