The Crystallization Of Egg-white Lysozyme Using Ionic Liquids In The Alkality Condition

Protein crystallography is an active interdisciplinary subject. The determination of structure of one protein crystal can not only provide the value of structure itself, but also help us to further comprehend the function of proteins, the relationship between proteins and diseases and drug design. Heretofore, biomacromolecule crystallization is a bottleneck in structural genomics. Therefore, it is necessary to make great efforts to innovate the crystallization methods, optimize the crystallization conditions, study the crystallization principles and the observation methods.Nowadays, ionic liquids (ILs) have been the focus in the chemistry field. And it is also used in life science field, especially in the biocatalyst reaction as solvent or cosolvent. Recently, ionic liquids are applied in protein crystallization.Lysozyme is one kind of proteins that are crystallized easily. At all the times, it is used widely as a model protein in the study of the protein crystallization machanincs and means. In this thesis, we pick up lysozyme as the investigated subject. Ionic liquids of [bmim][BF₄] and [bmim]Cl were prepared through Two-step Method and Direct Method, respectively. And the final products were characterized by Infrared spectra. For the further studies on the effects of the ILs on the crystal growth, the solubility of lysozyme was mensurated with ultraviolet-visible light spectrophotometer by the way of BCA method. It was shown that ionic liquid had similar effect as precipitants or additions. Then, optimal condition for lysozyme crystallization was confirmed by vapor diffusion technique. Some crystals, which had enough dimensions and high quality, were acquired with batch method under this condition.Furthermore, the influence of ionic liquid on protein crystallization was discussed through a group of contrasting experiment. The result showed that ionic liquid is a kind of excellent protein crystallization additive. In the process of protein crystallization, ionic liquid accelerates the growth of nucleus and affects the growth speed of crystallization. Protein crystal speed, size and quality may be controlled by adjusting content of ionic liquid.In this thesis, [bmim][BF₄] and [bmim]Cl are also used to prepare theegg-white lysozyme by crystallization directly. According to the results of thepreliminary crystallization and purification crystallization, it is found that[bmim][BF₄] can made the operation easier, the quality better and increase theefficiency of crystallization.It is still not clear about the principles of the effect of the ILs on the proteincrystallization. The study of the protein crystallization by using ILs is vacancy.There is a flourishing foreground in this field. And it needs more experts to devoteto the study deeply and widely.