Lysozyme conformational changes with ionic liquids: Spectroscopic, small angle x-ray scattering and crystallographic study
Lysozyme conformational changes with ionic liquids: Spectroscopic, small angle x-ray scattering and crystallographic study
复制标题
DOI：
10.1016/j.jcis.2020.10.024
复制
发表时间：
2021-03-01
影响因子：
9.9
通讯作者：
Greaves, Tamar L.
中科院分区：
文献类型：
--
作者：
Han, Qi;Smith, Kate M.;Greaves, Tamar L.
支持蛋白质功能的溶剂对生物化学应用很重要，需要新的溶剂。本文采用红外光谱、荧光光谱、小角x射线散射（SAXS）和x射线晶体学研究了离子液体（ILs）加入后溶菌酶的构象变化。光谱技术鉴定出溶菌酶的二级结构在较低的IL浓度为1和5 mol%时保持不变，尽管色氨酸环境在硝酸盐基IL的存在下显着改变。SAXS实验表明，溶菌酶的旋转半径在IL浓度为1 mol%时增大，随着IL浓度的增加而减小。三级结构，特别是环区，随着IL浓度的变化而变化，这取决于IL的类型。硝酸乙胺IL存在时溶菌酶的晶体结构证实了环区被延长，并鉴定出3个与硝酸盐离子结合的特异位点，带正电的区域为IL敏感区。这项工作提供了一个详细的了解溶菌酶构象的变化在存在的ILs。这种方法可以扩展到其他功能重要的蛋白质。(C) 2020爱思唯尔公司版权所有。
Solvents that support protein functionality are important for biochemical applications, and new solvents are required. Here we employ FTIR and fluorescence spectroscopies, small angle X-ray scattering (SAXS) and X-ray crystallography to understand conformational changes of lysozyme with ionic liquids (ILs) added. Spectroscopic techniques identified that the secondary structure of lysozyme was maintained at the lower IL concentrations of 1 and 5 mol%, though the Tryptophan environment was significantly altered with nitrate-based ILs present. SAXS experiments indicated that the radius of gyration of lysozyme increased with 1 mol% IL present, and then decreased with increasing IL concentrations. The tertiary structure, particularly the loop regions, changed as a function of IL concentration, and this depended on the IL type. The crystallographic structure of lysozyme with the IL of ethylammonium nitrate present confirmed the loop region was extended, and identified three specific binding sites with nitrate ions, and that the positively charged areas were IL sensitive regions. This work provides a detailed understanding of lysozyme conformational changes in the presence of ILs. This approach can be extended to other functionally-important proteins. (C) 2020 Elsevier Inc. All rights reserved.