Binding modes and in vitro digestion profiles of an iron-binding peptide (EEEWDRE) derived from fermented scallop skirts

Studies on the preparation of bioactive peptides by fermentation are rare, let alone the structural characterization of peptides. This study investigated the binding modes and digestion profiles of a novel heptapeptide (EEEWDRE) identified from fermented scallop skirts, which owned a excellent ferrous chelating rate of 92.44 ± 0.43 %. Specifically, the molecular docking, ITC and spectroscopy results of the heptapeptide‑iron complex (EEEWDRE-Fe) indicated that ferrous ions were chelated with EEEWDRE through "monodentate" and "bidentate" modes, each molecule of heptapeptide could bind three molecules of ferrous ions, and the carboxyl oxygen atom was the main binding site. Furthermore, EEEWDRE-Fe maintained a high ferrous chelating rate throughout the digestion process, consistently exceeding 80 %. The proportion of the "EEEW" sequence in EEEWDRE and EEEWDRE-Fe was 88.77 % and 90.21 %, respectively. "EEEW" was crucial in the formation of the EEEWDRE-Fe. Our findings provided novel insights into the unique properties of fermentation-derived peptides, highlighting their potential as iron supplements.