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

<p>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 (∆<i>G</i>) 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].</p

Ionic Liquid Influenced Synergistic Interaction between Amitriptyline Hydrochloride and Cetyl­trimethyl­ammonium Bromide

The mixed micellization behavior of amitriptyline hydrochloride (AMT) with cetyl­trimethyl­ammonium bromide (CTAB) has been studied at different mole fractions in the presence of imidazolium based ionic liquid 1-butyl-3-methyl imidazolium hydrochloride (Bmim·Cl), by using electrical conductivity at different temperatures from 298 to 318 K. A shift in the <i>T</i>_max value (i.e., the temperature at which the cmc value is maximized) has been observed with the rise in CTAB mole fraction. Synergistic interaction is explained by the deviations in critical micelle concentration (cmc) from an ideal critical micelle concentration (cmc*) and micellar mole fraction (<i>X</i>^m) from ideal micellar mole fraction (<i>X</i>^ideal) values. The calculated thermodynamic parameters (viz., the standard Gibbs energy change, Δ<i>G</i>_m^°, the standard enthalpy change, Δ<i>H</i>_m^°, and the standard entropy change, Δ<i>S</i>_m^°) suggest the dehydration of hydrophobic part of the drug at higher temperatures in the case of AMT as well as in CTAB-AMT binary systems in the presence of Bmim·Cl, whereas the temperature at which dehydration occurs changes with the rise in the mole fraction of CTAB

Enthalpy-driven interaction between dihydropyrimidine compound and bovine serum albumin: a spectroscopic and computational approach

Enthalpy-driven interaction between dihydropyrimidine compound and bovine serum albumin: a spectroscopic and computational approac