Effect of 1-methyl-3-octyleimmidazolium chloride on the stability and activity of lysozyme: a spectroscopic and molecular dynamics studies

Abstract

Herein, the binding of 1-methyl-3-octylimidazolium chloride [OMIM][Cl] ionic liquid with hen egg white lysozyme (HEWL) has been studied using fluorescence, time resolved fluorescence, UV-visible and circular dichroism (CD) spectroscopy, in combination with computational study. The fluorescence results revealed that [OMIM][Cl] quenches the fluorophore of HEWL through static quenching mechanism. The calculated thermodynamic parameters show that [OMIM][Cl] bind with HEWL through hydrophobic interactions. In addition, the negative value of Gibbs energy change (∆G) indicates that the binding process was spontaneous. Furthermore, UV-vis and CD results indicate that [OMIM][Cl] induce the conformational change in HEWL and increase its enzymatic activity. Additionally, molecular docking results showed that [OMIM][Cl] binds at the active site of HEWL where both the fluorophore residues (Trp108 and Trp62) and the catalytic residues (Glu35 and Asp52) reside. Molecular dynamic simulation results show the reduction of intra-molecular hydrogen bond of HEWL when it binds with [OMIM][Cl].

Esterase activity and conformational changes of bovine serum albumin toward interaction with mephedrone: Spectroscopic and computational studies

“…Moreover, we can also utilize this technique to confirm the effective quenching mechanism (static/ dynamic) between the ligand and the protein. The dynamic quenching involves and affects only the excited states of molecules and hence no change in absorption spectra is expected, while as in case of ground state complex formation (static quenching), the absorption spectra of the fluorophore get perturbed as happens in our case . The transitions from highest occupied molecular orbital to lowest unoccupied molecular orbital include σ → σ*, π → π*, n → σ*, and n → π*.…”

Unveiling the Influence of Non-Toxic Fluorinated Ionic Liquids Aqueous Solutions in the Encapsulation and Stability of Lysozyme

“…A specific family has grown in this direction, the surface-active ionic liquids (SAILs), which are characterized by their enhanced solubilization mechanisms due to their amphiphilic nature granted by the long cationic and/or anionic hydrogenated chains. The superior surface activity of SAILs compared with conventional surfactants allows self-assembly in aqueous solutions into more efficient colloidal systems, such as micelles or vesicles, with greater control of their shape, size, stability, and specific utility [7,[10][11][12][13][14][15][16]. These advantages highlight the substitution of surfactants by SAILs in the protein stability field, successfully demonstrated by some works in the specific case of lysozyme.…”

“…Mandal et al [12] studied the interactions between 1-butyl-3-methylimidazolium octylsulfate and lysozyme, discovering a destabilizing effect of the IL which highly depends on the variation of the solution pH and of the increment of IL concentration added to the solution. Kumari et al [13] highlighted the binding of 1-methyl-3-octylimidazolium chloride at the active site of lysozyme mainly by hydrophobic interactions, inducing conformational change by reducing the intramolecular hydrogen bond of the enzyme and enhancing the protein activity. In another work, Kumari et al [14] selected 1-decyl-3-methylimidazolium chloride as an additive to prevent protein aggregation.…”

The role of chlorine atom on the binding between acrylonitrile derivatives and fat mass and obesity‐associated protein

“…The interaction between the derivative and FTO is static quenching. The binding constant K a and the number of binding sites ( n ) can be obtained from the double logarithmic Equation ) 49‐51 : …”