β-Lactoglobulin as a potential carrier for bioactive molecules.

Area of Science:

• Biochemistry
• Materials Science
• Analytical Chemistry

Background:

• Bovine beta-lactoglobulin (LGB) is a major whey protein with potential applications in drug delivery.
• Understanding protein-ligand interactions is crucial for designing effective delivery systems.
• Tetracaine (TET) is an amphiphilic anesthetic with potential binding capabilities.

Purpose of the Study:

• To investigate the binding interactions between tetracaine (TET) and bovine beta-lactoglobulin (LGB) isoforms.
• To characterize the physicochemical properties of the LGB-TET complex under various conditions.
• To determine the binding sites and structural impact of TET on LGB.

Main Methods:

• Dynamic Light Scattering (DLS)
• Electrophoretic Mobility
• UV-Vis Spectroscopy
• Circular Dichroism (CD)
• Quartz Crystal Microbalance with Dissipation monitoring (QCM-D)
• Molecular Docking

Main Results:

• Tetracaine (TET) binds to bovine beta-lactoglobulin (LGB) both internally (beta-barrel) and externally (surface).
• TET binding increases LGB's positive charge (zeta potential) primarily above pH 6 due to electrostatic interactions.
• Circular Dichroism (CD) indicated no significant alteration in LGB's secondary structure upon TET binding.
• Quartz Crystal Microbalance (QCM-D) data revealed the properties of the adsorbed LGB-TET complex on a gold surface.

Conclusions:

• Tetracaine (TET) exhibits dual binding modes with bovine beta-lactoglobulin (LGB), involving both surface and internal interactions.
• The interaction is pH-dependent, leading to increased positive surface charge on LGB above pH 6.
• LGB's secondary structure remains intact, suggesting stable complex formation suitable for potential applications.