Ovalbumin, ovotransferrin, lysozyme: three model proteins for structural modifications at the air-water interface.
Structural modifications of ovalbumin, ovotransferrin, and lysozyme at the air-water interface have been investigated using SDS-PAGE, both intrinsic and ANS fluorometry, and circular dichroism experiments. Ovalbumin contact with an interface induced an exposure of aromatic residues, a slight decrease in alpha-helix structures (-1.7%), and an increase in both beta-sheet (+3.4%) and beta-turn (+7.9%) structures. Moreover, these conformational changes led to the formation of insoluble polymers of ovalbumin through intermolecular disulfide bonds. Ovotransferrin contact with an interface led to an increase in its surface hydrophobicity (+30%) and modifications of its secondary structure (-33% of alpha-helices, +96.4% of beta-sheets, +13.2% of beta-turns, and +21.2% of random coils), characteristic of major conformational changes. On the other hand, lysozyme did not undergo any structural modification. These results clearly underscore that at the air-water interface proteins are susceptible to denaturation.
D000388:Air; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002942:Circular Dichroism; D003207:Conalbumin / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D005470:Fluorometry; D009113:Muramidase / Q000737:chemistry*; D010047:Ovalbumin / Q000737:chemistry*; D011487:Protein Conformation; D011489:Protein Denaturation; D014867:Water / Q000737:chemistry*
D014867:Water; D003207:Conalbumin; D010047:Ovalbumin; D009113:Muramidase