Protic Ionic Liquid Cation Alkyl Chain Length Effect on Lysozyme Structure.
Protic Ionic Liquid Cation Alkyl Chain Length Effect on Lysozyme Structure.
复制标题
DOI：
10.3390/molecules27030984
复制
发表时间：
2022-02-01
期刊：
影响因子：
--
通讯作者：
Greaves TL
中科院分区：
文献类型：
--
作者：
Han Q;Broomhall HC;Vieira Veríssimo N;Ryan TM;Drummond CJ;Pereira JFB;Greaves TL
稳定蛋白质结构的溶剂可以改善和扩展其生化应用，特别是随着人们对基于生物催化的工艺越来越感兴趣。为了选择用于稳定蛋白质的新型溶剂，我们探讨了增加阳离子烷基链长度的硝酸烷基铵质子离子液体（PIL）-水混合物对溶菌酶构象稳定性的影响。研究了四种 PIL，即硝酸乙基铵 (EAN)、硝酸丁基铵 (BAN)、硝酸己基铵 (HAN) 和硝酸辛基铵 (OAN)。首先测定了低浓度到高浓度的 PIL-水混合物的表面张力、粘度和密度，结果表明，阳离子烷基链长度的增加导致所有 PIL 溶液的表面张力和密度降低以及粘度增加。小角 X 射线散射 (SAXS) 用于研究 PIL 溶液的液体纳米结构，以及整体尺寸、构象灵活性和溶菌酶结构的变化。具有较长烷基链长度的浓缩 PIL，即超过 10 mol% 丁基、5 mol% 己基和 1 mol% 辛基铵阳离子，具有液体纳米结构。这对溶剂扣除产生不利干扰，并且结构更结构化的 PIL 溶液阻碍了溶菌酶结构的定量 SAXS 分析。在结构较少的 PIL 水溶液中，溶菌酶的回转半径 (Rg) 在 PIL 浓度高达 10 mol% 时几乎没有变化。 Kratky 图、SREFLEX 模型和 FTIR 数据表明，与缓冲溶液相比，蛋白质构象在 1 mol% 的低 PIL 浓度下得以维持。然而，50 mol% EAN 和 5 mol% HAN 显着增加了溶菌酶的 Rg，表明溶菌酶发生去折叠和聚集。 HAN 中阳离子烷基链长度增加导致的疏水相互作用和液体纳米结构可能变得至关重要。 FTIR 进一步揭示了 HAN 和 OAN（特别是高浓度时）对溶菌酶结构的影响。这项工作强调了长烷基链长度和高浓度 PIL 对溶菌酶结构稳定性的负面影响。
Solvents that stabilize protein structures can improve and expand their biochemical applications, particularly with the growing interest in biocatalytic-based processes. Aiming to select novel solvents for protein stabilization, we explored the effect of alkylammonium nitrate protic ionic liquids (PILs)-water mixtures with increasing cation alkyl chain length on lysozyme conformational stability. Four PILs were studied, that is, ethylammonium nitrate (EAN), butylammonium nitrate (BAN), hexylammonium nitrate (HAN), and octylammonium nitrate (OAN). The surface tension, viscosity, and density of PIL-water mixtures at low to high concentrations were firstly determined, which showed that an increasing cation alkyl chain length caused a decrease in the surface tension and density as well as an increase in viscosity for all PIL solutions. Small-angle X-ray scattering (SAXS) was used to investigate the liquid nanostructure of the PIL solutions, as well as the overall size, conformational flexibility and changes to lysozyme structure. The concentrated PILs with longer alkyl chain lengths, i.e., over 10 mol% butyl-, 5 mol% hexyl- and 1 mol% octylammonium cations, possessed liquid nanostructures. This detrimentally interfered with solvent subtraction, and the more structured PIL solutions prevented quantitative SAXS analysis of lysozyme structure. The radius of gyration (Rg) of lysozyme in the less structured aqueous PIL solutions showed little change with up to 10 mol% of PIL. Kratky plots, SREFLEX models, and FTIR data showed that the protein conformation was maintained at a low PIL concentration of 1 mol% and lower when compared with the buffer solution. However, 50 mol% EAN and 5 mol% HAN significantly increased the Rg of lysozyme, indicating unfolding and aggregation of lysozyme. The hydrophobic interaction and liquid nanostructure resulting from the increased cation alkyl chain length in HAN likely becomes critical. The impact of HAN and OAN, particularly at high concentrations, on lysozyme structure was further revealed by FTIR. This work highlights the negative effect of a long alkyl chain length and high concentration of PILs on lysozyme structural stability.
登录
查看更多内容
影响因子：
9.8
作者：
Jessop, Philip G.
通讯作者：
Jessop, Philip G.
影响因子：
3.3
作者：
Greaves, Tamar L.;Kennedy, Danielle F.;Drummond, Calum J.
通讯作者：
Drummond, Calum J.
影响因子：
16.6
作者：
Hayes, Robert;Imberti, Silvia;Atkin, Rob
通讯作者：
Atkin, Rob
影响因子：
14.8
作者：
Jeffries CM;Graewert MA;Blanchet CE;Langley DB;Whitten AE;Svergun DI
通讯作者：
Svergun DI
影响因子：
9.9
作者：
Han, Qi;Smith, Kate M.;Greaves, Tamar L.
通讯作者：
Greaves, Tamar L.