title: Role of the N-terminal amphiphilic region of ovalbumin during heat-induced aggregation and gelation.
abstract: Ovalbumin (OVA), a major globular protein in egg white, forms semiflexible fibrillar aggregates during heat-induced gelation. The N-terminal amphiphilic region (pN1-22) of OVA is removed after treatment with pepsin at pH 4 to leave a large OVA fragment (pOVA). The conformation and thermal stability of pOVA and OVA are similar, but the rheological strength of the heat-induced gel of pOVA is much lower compared to that of OVA. The aggregation rate of pOVA, which forms spherical aggregates, was lower than that of OVA. These results suggest that the N-terminal amphiphilic region of OVA facilitates the α-to-β conformational transition, which triggers OVA fibril formation. Heat treatment of OVA in the presence of pN1-22 consistently resulted in the formation of straight fibrils. The strength of OVA and collagen gels was increased when prepared in the presence of pN1-22, suggesting that pN1-22 may be used to control the properties of protein gels.
authors.affiliation: Department of Bio-molecular Engineering, Kyoto Institute of Technology , Matsugasaki, Sakyo, Kyoto 606-8585, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kawachi
authors.forename: Rina
authors.initials: R
authors.lastname: Kameyama
authors.forename: Akihiro
authors.initials: A
authors.lastname: Handa
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Takahashi
authors.forename: Naoki
authors.initials: N
authors.lastname: Tanaka
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry; D055598:Chemical Phenomena; D005782:Gels / Q000737:chemistry; D006358:Hot Temperature; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010047:Ovalbumin / Q000737:chemistry* / Q000648:ultrastructure; D010446:Peptide Fragments / Q000737:chemistry*; D012212:Rheology; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D000682:Amyloid; D005782:Gels; D010446:Peptide Fragments; D013501:Surface-Active Agents; D010047:Ovalbumin