Agro-industrial by-products-bioinspired pure peptides: Their self-assembly via Cu2+ ion coordination, structure, mechanical properties and antioxidant activity

We investigated the effect of Cu 2+ coordination on the self-assembly behavior and in vivo antioxidant properties of 4 synthetic peptides bioinspired from food protein sequences derived from agro-industrial byproducts (sunflower meal and tilapia scales) under Cu 2 + −induced oxidative stress using Caenorhabditis elegans . The peptides were selected based on their structural features and potential coordination sites, which enabled us to evaluate peptide-Cu 2+ interactions. First, their Cu 2 + −chelating ability was assessed using the PV assay. Then, spectroscopic characterization was performed to reveal coordination modes and conformational changes. Molecular docking was then used to predict binding energies and interaction patterns. Upon Cu 2+ coordination, significant changes in peptide organization were observed, indicating that coordination can influence molecular arrangement and potentially encourage ordered self-assembly based on specific sequence characteristics. All peptide-Cu 2+ complexes exhibited the ability to reduce intracellular reactive oxygen species (ROS) levels in C. elegans , demonstrating in vivo antioxidant activity. Pep1.G H RGFSGL exhibited the strongest effect, consistent with its higher Cu 2 + −chelating ability and favorable binding energy. This finding underscores the importance of coordination mode and sequence composition. These results unveil new insights into the molecular-level mechanisms by which Cu 2+ coordination governs peptide self-assembly and bioactivity. Using well-defined synthetic peptides bioinspired by agro-industrial protein sources, such as sunflower meal and tilapia scales, this study deepens our understanding of the previously observed behavior in complex hydrolysates, where peptide heterogeneity limits mechanistic interpretation. The findings underscore the capacity of food-derived peptide sequences to form metal-induced nanostructures with customized functional properties, suggesting their potential application in functional foods and nutraceuticals.