Journal of Molecular Liquids ( IF 5.3 ) Pub Date : 2019-06-27 , DOI: 10.1016/j.molliq.2019.111229
Anu Aravind Thoppil , Bharath Kumar Chennuri , Ramesh L. Gardas
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Ionic liquids (ILs) owing to their unique and tunable physicochemical properties have found profound applications in the biomedical and pharmaceutical field. Since ILs are widely used as solubilizing and stabilizing agents for biomolecules. It is important to explore their effect on proteins. Surface active ionic liquids (SAILs) due to their higher surface activity and tunable property have emerged as new task specific ILs and found to have superior properties than conventional ionic surfactants. In this work, we have synthesized and characterized two novel ethanolammonium based SAILs, namely, (n-butylethanolammonium laurate [NBEA][LAU] and tert-butylethanolammonium laurate [TBEA][LAU]). The self-assembling behavior of the SAILs in pure water was examined by tensiometry and conductometry. The structural changes occurring in BSA as the consequence of interactions with SAILs at pH 7.4 and T = 298.15 K were explored using steady-state and life time fluorescence, UV–Visible and far UV circular dichroism(CD) spectroscopy and isothermal titration calorimetry (ITC). The results from surface tension and conductivity measurements give the values of critical micelle concentration (cmc) of the BSA-SAIL complex formation. The CD spectroscopy gives information on the secondary structure alterations of BSA-SAIL complex, which is further confirmed by ITC data. The dynamic quenching effect in tryptophan fluorescence of BSA is significant as evidenced by lifetime measurements. Overall, the present work highlights the conformational changes the protein can undergo upon interacting with SAILs.
中文翻译:
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洞察乙醇酸月桂酸铵基表面活性离子液体中牛血清白蛋白的结构变化
离子液体(ILs)由于其独特且可调节的物理化学特性,已在生物医学和制药领域中得到了广泛的应用。由于IL被广泛用作生物分子的增溶剂和稳定剂。重要的是探索它们对蛋白质的作用。由于表面活性离子液体(SAIL)具有更高的表面活性和可调节的特性,它们已作为新的任务特定IL出现,并被发现比传统的离子表面活性剂具有更好的性能。在这项工作中,我们合成并表征了两种新型的基于乙醇铵的SAIL,即(月桂酸正丁基乙醇铵[NBEA] [LAU]和月桂酸叔丁基乙醇铵[TBEA] [LAU])。通过张力测定法和电导测定法检查了SAIL在纯水中的自组装行为。T = 298.15 K是使用稳态和寿命荧光,紫外可见和远紫外圆二色性(CD)光谱和等温滴定热量(ITC)进行探索的。表面张力和电导率测量的结果给出了BSA-SAIL配合物形成的临界胶束浓度(cmc)的值。CD光谱学提供了有关BSA-SAIL复合物二级结构改变的信息,ITC数据进一步证实了这一点。如寿命测量所证明的,BSA色氨酸荧光中的动态猝灭作用是显着的。总的来说,本工作突出了蛋白质与SAIL相互作用后可能发生的构象变化。