Stability strategy of astaxanthin in Antarctic krill muscle: Insights from proteomics and docking simulation

Astaxanthin is the most representative bioactive substance of Antarctic krill. However, the intrinsic stabilization mechanism mediated by endogenous soluble protein fractions in krill muscle has yet to be elucidated at the molecular level. In this study, the binding capacity of different solubilizing fractions to astaxanthin was significantly different (p < 0.05). The linear, non-saturating binding curves of fractions B, D, and F suggested a typical non-specific, multi-site surface adsorption mechanism. Electrophoretic protein profiles of the six solubilized fractions were readily distinguishable. Proteomic analysis identified potential astaxanthin-binding proteins, including hemocyanin, lipoprotein and α-actinin, with molecular weights mostly above 30 kDa. Molecular docking analysis revealed that hydrogen bond and hydrophobic interactions were the main driving forces. Molecular dynamics simulations further confirmed that hemocyanin showed good binding stability, while α-actinin had more flexible interactions. These findings offer insights into astaxanthin-protein interactions and a stabilization strategy to facilitate broader applications of carotenoids.