Effects of high hydrostatic pressure on conformation and IgG binding capacity of tropomyosin in Pacific oyster (Crassostrea gigas)

Abstract

To investigate the effects of high hydrostatic pressure (HHP) on the conformation and IgG binding capacity, tropomyosin (TM) from Pacific oysters was subjected to high pressures of 300, 450 or 600 MPa. The results showed that the α-helix of TM with HHP-induced was decreased, while β-turn, β-sheet (predominantly) and random coil were increased. The surface hydrophobicity and sulfhydryl group content of TM were increased, while the fluorescence/UV intensity were decreased after HHP treatment. Atomic force microscopy (AFM) result exhibited that the morphology of TM was changed at 600 MPa and formed fibrous structures. The IgG binding capacity of TM and digested TM was markedly reduced when the pressure was increased, especially at 600 MPa. Overall, this study indicated that HHP-induced conformational changes in TM contributed to the reduction in IgG binding capacity. These findings suggested that HHP may be a promising non-thermal technology for producing hypoallergenic oyster products.

Keywords: High hydrostatic pressure; IgG binding capacity; Pacific oyster; Protein conformation; Tropomyosin.