Insight into the mechanism of allergenicity decreasing in recombinant sarcoplasmic calcium-binding protein from shrimp (Litopenaeus vannamei) with thermal processing via spectroscopy and molecular dynamics simulation techniques

Abstract

In the present study, sarcoplasmic calcium-binding protein (SCP) was first expressed in E. coli BL21 (DE3), and then identified based on immunoblotting and SCP amino acid sequencing of shrimp (Litopenaeus vannamei) using mass spectrometry (MS). The recombinant SCP (rSCP) was treated with different temperature conditions to investigate its immunological properties, in vitro digestibility and structural changes with enzyme-linked immunosorbent assay (ELISA), immunoblotting, spectrophotometry and molecular dynamics simulation techniques. The immunoglobulin (Ig) E-binding activity of the rSCP could remain stable until 80 °C, whereas the higher thermal processing temperatures resulted in a significant decrease in IgG/IgE-binding capacity coupled with alterations in the secondary and tertiary structures. Notably, the maximum reduction of IgG/IgE reactivity and in vitro digestibility were observed in the autoclaved rSCP. The decrease in the potential allergenicity of rSCP not only correlated well with the decreasing of α-helix, epitopes masking and exposure of more protease cleavage sites, but also with the destruction of Ca2+ binding sites due to the unfolding of the rSCP with heating treatments, which was supported by the thermal-induced changes of the secondary and tertiary structures. These findings indicate that autoclaved treatment may be an effective and promising approach for producing hypoallergenic seafood.