Using Ionic Liquids in Protein Crystallization

E. Tutubalina¹, B. Minofar³, I. Kuta Smatanova^1,2,3

¹University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05 Ceske Budejovice

²University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, CENAKVA and Institute of Complex Systems, Zamek 136, 373 33 Nove Hrady

³Academy of Sciences of the Czech Republic, Institute of Nanobiology and Structural Biology GCRC, Zamek 136, 373 33 Nove Hrady

Ionic liquids (ILs) are organic salts composed of separate cations and anions, which are liquid at room temperature and virtually have zero vapor pressure. ILs possess cationic and anionic components that can be tailored for different applications however the properties of ILs are not known well. ILs have been reported to influence on thermal stability, to stabilize protein structure and activity, to increase crystallization rates and crystal size, to enhance the kinetics of crystallization.

The investigation of using ionic liquids as additives for advanced crystallization was held. Twenty four ILs were incorporated in the experiment for their effect on the lysozyme and thaumatin crystallization using Ionic Liquid Screen kit. Experiments were set up with 50% w/v ILs added to the crystallization solutions at ration 1:9. Crystallization droplets were set up at four protein/precipitant ratios - 1:1, 1:2, 2:1, 3:1. Crystals were obtained under identical conditions that are optimal for common lysozyme and thaumatin crystallization.

Sitting Drop Vapor Diffusion crystallization experiments showed that addition of some of the ILs led to less crystal polymorphism and larger the lysozyme crystals.

This research is supported by the GACR (P207/12/0775), ME CR (CZ.1.05/2.1.00/01.0024) and by the AS CR.