Interaction of Lysozyme with Monocationic and Dicationic Ionic Liquids: Toward Finding a Suitable Medium for...

Area of Science:

• Biochemistry
• Physical Chemistry
• Materials Science

Background:

• Ionic liquids (ILs) are versatile solvents with tunable properties.
• Understanding IL-protein interactions is crucial for biomaterial and pharmaceutical applications.
• Monocationic (MILs) and dicationic (DILs) ILs exhibit distinct structural and physicochemical characteristics.

Purpose of the Study:

• To investigate and compare the binding interactions of lysozyme with MILs and a DIL.
• To elucidate the influence of IL cation hydrophobicity and structure on protein behavior.
• To determine which type of IL better preserves native protein structure.

Main Methods:

• Steady-state and time-resolved fluorescence spectroscopy for ensemble-averaged measurements.
• Fluorescence correlation spectroscopy (FCS) for single-molecule dynamics.
• Circular dichroism (CD) spectroscopy to assess protein secondary structure changes.

Main Results:

• MILs and DILs interact differently with lysozyme.
• DILs induced significantly less change in protein structure and dynamics compared to MILs.
• Hydrophobicity and cationic structure of ILs influence protein interaction.

Conclusions:

• Imidazolium-based DILs are more effective than MILs in preserving the native structure of proteins in aqueous media.
• The choice of IL cation structure is critical for minimizing protein denaturation.
• Findings provide insights for designing stabilizing agents for proteins using ILs.