Ovalbumin, ovotransferrin, lysozyme: three model proteins for structural modifications at the air-water interface

Area of Science:

• Protein chemistry
• Biophysical chemistry
• Surface science

Background:

• Proteins are susceptible to conformational changes when exposed to interfaces.
• Understanding protein behavior at the air-water interface is crucial for various applications, including food science and biomaterials.

Purpose of the Study:

• To investigate the structural modifications of ovalbumin, ovotransferrin, and lysozyme at the air-water interface.
• To determine the susceptibility of these proteins to denaturation upon interface contact.

Main Methods:

• Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)
• Intrinsic and ANS (8-anilino-1-naphthalenesulfonic acid) fluorometry
• Circular dichroism (CD) spectroscopy

Main Results:

• Ovalbumin exhibited increased aromatic residue exposure, altered secondary structures (decreased alpha-helix, increased beta-sheet and beta-turn), and formed insoluble polymers via disulfide bonds.
• Ovotransferrin showed increased surface hydrophobicity and significant secondary structure modifications (decreased alpha-helix, increased beta-sheet, beta-turn, and random coil).
• Lysozyme demonstrated no significant structural modifications upon contact with the air-water interface.

Conclusions:

• The air-water interface can induce significant denaturation and structural changes in proteins like ovalbumin and ovotransferrin.
• Protein susceptibility to interface-induced denaturation varies, as evidenced by the stability of lysozyme.
• These findings highlight the importance of considering interfacial effects on protein structure and function.