Department of Chemistry, University of Kashmir, Srinagar 190006, J & K, India.
Department of Clinical Biochemistry, University of Kashmir, Hazratbal, 190006 Srinagar, J & K, India.
Int J Biol Macromol. 2020 Aug 1;156:271-279. doi: 10.1016/j.ijbiomac.2020.04.033. Epub 2020 Apr 11.
The present study was designed to explore the hydrophobicity and concentration dependence of imidazolium based surface active ionic liquids (SAILs) effects on the structural-functional integrity of proteins. Specifically, we investigated the impact of SAILs viz. 1-octyl-3-methylimidazolium dodecylbenzenesulfonate ([OMIM][DBS]) and 1-dodecyl-3-methylimidazolium dodecylbenzenesulfonate ([DDMIM][DBS]) on activity, structure and stability of lysozyme. Activity measurements revealed that, in contrast to [DDMIM][DBS] that renders lysozyme either feebly active or inactive, [OMIM][DBS] significantly enhances the lysozyme activity in the concentration range of critical aggregation concentrations (CAC) to C (SAIL saturation concentration of protein backbone) i.e., 0.5 mM-1.35 mM. Tensiometric results in agreement with turbidity measurements inferred significant composition and concentration dependence of the lysozyme-SAIL interactions. Spectroscopic investigations revealed that compared to destabilizing behaviour of [DDMIM][DBS], [OMIM][DBS] significantly enhances both conformational as well as thermal stability of lysozyme in the CAC to C concentration regime. Altogether, results obtained do indicate that [OMIM][DBS], in the concentration regime of CAC to C, serves as an efficient stabiliser with an ability to appreciably enhance the activity, thermal stability and overall conformational stability of lysozyme. We firmly believe that [OMIM][DBS], at least in the CAC to C concentration ranges, can be exploited as a promising stabiliser and activity enhancer for numerous industrially important enzymes.
本研究旨在探索基于咪唑的表面活性离子液体（SAIL）的疏水性和浓度依赖性对蛋白质结构-功能完整性的影响。具体而言，我们研究了 SAILs 对溶菌酶活性、结构和稳定性的影响，所研究的 SAILs 为 1-辛基-3-甲基咪唑十二烷基苯磺酸盐([OMIM][DBS])和 1-十二烷基-3-甲基咪唑十二烷基苯磺酸盐([DDMIM][DBS])。活性测量结果表明，与使溶菌酶活性减弱或失活的[DDMIM][DBS]相反，[OMIM][DBS]在临界聚集浓度（CAC）至 C（SAIL 与蛋白质主链的饱和浓度）的浓度范围内显著增强了溶菌酶的活性，即 0.5 mM-1.35 mM。与浊度测量结果一致的张力测量结果推断出溶菌酶-SAIL 相互作用具有显著的组成和浓度依赖性。光谱研究表明，与[DDMIM][DBS]的去稳定行为相比，[OMIM][DBS]在 CAC 至 C 的浓度范围内显著增强了溶菌酶的构象和热稳定性。总之，研究结果表明，[OMIM][DBS]在 CAC 至 C 的浓度范围内，作为一种有效的稳定剂，可以显著提高溶菌酶的活性、热稳定性和整体构象稳定性。我们坚信，[OMIM][DBS]至少在 CAC 至 C 的浓度范围内，可以作为许多工业上重要的酶的有前途的稳定剂和活性增强剂。
