Crystal Morphology and Molecular Interaction of Lysozyme Affected by Imidazolium-Based Ionic Liquids in Aqueous Solutions

The protein crystallization is a complex physical and chemical process. The high-quality protein crystal is still a persistent bottleneck to the application of X-ray crystallography in structural biology. The additives may promote formation of crystal nucleus and subsequent growth in protein crystallization. As a distinct material, ionic liquids (ILs) have aroused great attentions and interests for protein crystallization due to their unique properties. In this paper, the application of ILs into protein crystallization has been reviewed in this paper. A research about lysozyme morphology control by ionic liquids, as crystal growth template, in aqueous solutions has been performed. It is worth noting that ILs encourage changes in some cases in terms of growth morphology and crystal size. The effect of ILs on lysozyme growth morphology can be attributed to changing interaction among lysozyme molecules in aqueous solutions. A study on molecular interaction in the presence ILs based on solubility and Raman spectroscopy were performed. Our study is especially helpful to control crystal growth and morphology for protein and to gain initial insight into the preparation of high quality crystal and the development of new crystal form as well as the design optimization of protein crystallization.