Satish Lakkoji, Millan Sabera, Sahoo Harekrushna
Department of Chemistry, National Institute of Technology Rourkela, Rourkela, Odisha, India.
Luminescence. 2017 Aug;32(5):695-705. doi: 10.1002/bio.3239. Epub 2016 Nov 3.
The study of protein-ionic liquid interactions is very important because of the widespread use of ionic liquids as protein stabilizer in the recent years. In this work, the interaction of bovine serum albumin (BSA) with different imidazolium-based ionic liquids (ILs) such as [1-ethyl-3-methyl-imidazolium ethyl sulfate (EmimESO ), 1-ethyl-3-methyl-imidazolium chloride (EmimCl) and 1-butyl-3-methyl-imidazolium chloride (BmimCl)] has been investigated using different spectroscopic techniques. The intrinsic fluorescence of BSA is quenched by ILs by the dynamic mechanism. The thermodynamic analysis demonstrates that very weak interactions exist between BSA and ILs. 8-Anilino-1-naphthalenesulfonic acid (ANS) fluorescence and lifetime measurements reveal the formation of the compact structure of BSA in IL medium. The conformational changes of BSA were monitored by CD analysis. Temperature-dependent ultraviolet (UV) measurements were done to study the thermal stability of BSA. The thermal stability of BSA in the presence of ILs follows the trend EmimESO > EmimCl > BmimCl and in the presence of more hydrophobic IL, destabilization increases rapidly as a function of concentration.
近年来，离子液体作为蛋白质稳定剂被广泛使用，因此蛋白质与离子液体相互作用的研究非常重要。在这项工作中，使用不同的光谱技术研究了牛血清白蛋白（BSA）与不同的咪唑基离子液体（ILs），如[1-乙基-3-甲基咪唑硫酸乙酯（EmimESO）、1-乙基-3-甲基咪唑氯盐（EmimCl）和1-丁基-3-甲基咪唑氯盐（BmimCl）]之间的相互作用。ILs通过动态机制淬灭了BSA的固有荧光。热力学分析表明，BSA与ILs之间存在非常弱的相互作用。8-苯胺基-1-萘磺酸（ANS）荧光和寿命测量揭示了在IL介质中BSA形成了紧密结构。通过圆二色性（CD）分析监测了BSA的构象变化。进行了温度依赖性紫外（UV）测量以研究BSA的热稳定性。在ILs存在下，BSA的热稳定性遵循EmimESO > EmimCl > BmimCl的趋势，并且在存在更多疏水性IL的情况下，失稳随着浓度的增加而迅速增加。
