Nanostructure, Self-Assembly, Mechanical Properties, and Antioxidant Activity of a Lupin-Derived Peptide Hydrogel

Abstract

Naturally occurring food peptides are frequently used in the life sciences due to their beneficial effects through their impact on specific biochemical pathways. Furthermore, they are often leveraged for applications in areas as diverse as bioengineering, medicine, agriculture, and even fashion. However, progress toward understanding their self-assembling properties as functional materials are often hindered by their long aromatic and charged residue-enriched sequences encrypted in the parent protein sequence. In this study, we elucidate the nanostructure and the hierarchical self-assembly propensity of a lupin-derived peptide which belongs to the α-conglutin (11S globulin, legumin-like protein), with a straightforward N-terminal biotinylated oligoglycine tag-based methodology for controlling the nanostructures, biomechanics, and biological features. Extensive characterization was performed via Circular Dichroism (CD) spectroscopy, Fourier Transform Infrared spectroscopy (FT-IR), rheological measurements, and Atomic Force Microscopy (AFM) analyses. By using the biotin tag, we obtained a thixotropic lupin-derived peptide hydrogel (named BT13) with tunable mechanical properties (from 2 to 11 kPa), without impairing its spontaneous formation of β-sheet secondary structures. Lastly, we demonstrated that this hydrogel has antioxidant activity. Altogether, our findings address multiple challenges associated with the development of naturally occurring food peptide-based hydrogels, offering a new tool to both fine tune the mechanical properties and tailor the antioxidant activities, providing new research directions across food chemistry, biochemistry, and bioengineering.

A New Polysaccharide Carrier Isolated from Camelina Cake: Structural Characterization, Rheological Behavior, and Its Influence on Purple Corn Cob Extract’s Bioaccessibility

“…Overall, the effects of vegetable carrier agents such as polysaccharides or gums on polyphenols during digestion have been widely investigated [ 22 , 38 ]; and by preserving these compounds from degradation and enhancing their solubility in the intestinal fluids, their bioprotective effects could be maintained, or sometimes enhanced [ 39 ].…”

“…To evaluate the storage (G’) and loss (G”) moduli of CCP, frequency sweep experiment results were recorded as a function of angular frequency (0.1–100 Hz) at 0.5% fixed strain. To test CCP thixotropy, shear-thinning tests were performed by a series of peak hold tests in which shear rates were kept constant, as previously reported by Pugliese et al, (2021) [ 22 ]. Briefly, a shear rate of 0.01 s −1 and a shear rate of 5.3 s −1 were applied in sequence for 60 and 20 s, respectively.…”

Lupin-Derived Bioactive Peptides: Intestinal Transport, Bioavailability and Health Benefits

“…To circumvent the limitation of biostability and bioavailability generally observed post-ingestion of peptides, the use of biocompatible carriers to deliver peptides are recommended. For instance, preparation of α-conglutin, a lupin-originated polypeptide, as a hydrogel has been shown to enhance its radical scavenging property [ 85 , 86 ], supporting the opinion that the practical-scale application of the multifunctional potentials of lupin-derived peptides are currently being explored.…”

“…This process is facilitated by specific cell membrane proteins and favors short-chain peptides [ 153 , 154 ]. While some bioactive peptides are linearly transported in an intact form across the intestinal epithelium to bind to their target and elicit biological response, others act as “prodrugs” and as such are transformed to their active metabolites during transport across the intestine by proteases and in circulation by serum peptidases [ 85 ].…”

Gel-Forming of Self-Assembling Peptides Functionalized with Food Bioactive Motifs Modulate DPP-IV and ACE Inhibitory Activity in Human Intestinal Caco-2 Cells

“…However, such food-derived peptides show low stability, bioavailability (due to their rapid degradation by active peptidases located on the intestinal microvilli), and a poor propensity to form functional biomaterials (i.e., hydrogels), thus precluding their practical applications. As we previously reported, one strategy to deal with these issues might be the use of well-designed and controlled self-assembled supramolecular systems, such as self-assembling peptides (SAPs) to be combined with the bioactive peptides in order to create hybrid systems, in which monomers are non-covalently bonded [ 6 , 7 , 8 , 9 ]. Indeed, when Soy1 and Lup1 were non-covalently entrapped into the RADA16 self-assembling peptide, the stability of both peptides was significantly improved as well as their capability of inhibiting DPP-IV and ACE, suggesting that this strategy could be a viable platform for targeting metabolic diseases [ 10 ].…”