Structural-functional integrity of lysozyme in imidazolium based surface active ionic liquids.

Area of Science:

• Biochemistry and Biophysics
• Materials Science
• Chemical Engineering

Background:

• Surface-active ionic liquids (SAILs) are amphiphilic compounds with unique properties.
• Understanding SAILs' interaction with biomolecules like proteins is crucial for various applications.
• Imidazolium-based SAILs are widely studied for their potential in biological systems.

Purpose of the Study:

• To investigate the impact of two imidazolium-based SAILs, [OMIM][DBS] and [DDMIM][DBS], on the activity, structure, and stability of lysozyme.
• To explore the concentration-dependent effects of these SAILs on protein integrity.
• To determine the potential of SAILs as protein stabilizers and activity enhancers.

Main Methods:

• Lysozyme activity assays were performed.
• Tensiometry and turbidity measurements were used to study protein-SAIL interactions.
• Spectroscopic techniques (UV-Vis, fluorescence, circular dichroism) were employed to assess structural and thermal stability.
• Critical aggregation concentrations (CAC) and SAIL saturation concentrations (Cs) were determined.

Main Results:

• [OMIM][DBS] significantly enhanced lysozyme activity between 0.5 mM and 1.35 mM (CAC to Cs).
• [DDMIM][DBS] reduced or eliminated lysozyme activity.
• SAILs showed significant composition and concentration-dependent interactions with lysozyme.
• [OMIM][DBS] improved both conformational and thermal stability of lysozyme within the CAC to Cs range, unlike [DDMIM][DBS].

Conclusions:

• [OMIM][DBS] acts as an effective stabilizer and activity enhancer for lysozyme within the CAC to Cs concentration range.
• The findings suggest potential applications of [OMIM][DBS] as a stabilizer for industrially relevant enzymes.
• Hydrophobicity and concentration of SAILs play critical roles in their effects on protein structure and function.