Macromolecular complexes of BSA with gelatin

Area of Science:

• Biophysics
• Materials Science
• Physical Chemistry

Background:

• Gelatin undergoes a helix-coil transition affecting its structural properties.
• Bovine Serum Albumin (BSA) is a common protein used in various applications.
• Understanding protein-protein interactions is crucial for biomaterial development.

Purpose of the Study:

• To investigate the impact of gelatin's conformational state on water-gelatin-BSA complex formation.
• To elucidate the mechanisms of intermacromolecular interactions under different temperature conditions.

Main Methods:

• Dynamic Light Scattering (DLS)
• Environmental Scanning Electron Microscopy (ESEM)
• Rheometry
• Differential Scanning Microcalorimetry (DSC)
• Circular Dichroism (CD) spectroscopy
• Fluorescence and absorption spectroscopy

Main Results:

• Above 40 °C, gelatin collapse forms compact BSA-gelatin complexes (∼30 nm radius, ∼6:1 mole/mole), enhancing gelatin's secondary structure and stabilizing BSA against thermal aggregation.
• Below 18 °C, gelatin network trapping forms large complex particles (600-1000 nm radius), significantly increasing system's storage and loss moduli.
• Thermodynamic parameters of BSA and gelatin thermal transitions remain largely unchanged.

Conclusions:

• The conformational state of gelatin dictates the structure and interaction mechanism within BSA-gelatin complexes.
• Temperature-dependent interactions influence complex size, stability, and rheological properties.
• This study provides insights into controlling complex formation for potential applications in biomaterials and food science.