STRUCTURAL ANALOGUES OF BIOACTIVE POLYPEPTIDES FROM SUSTAINABLE SOURCES: THE CASES OF QUINOA CHENOPODIN, COWPEA BETA-VIGNIN AND SOYBEAN GLYCININ

Bioactive polypeptides represent a rapidly growing trend in high-tech applications, ranging from human and animal well-being to next-generation plant defence strategies. However, conventional production methods frequently face limitations in terms of environmental impact, cost, and scalability. Moreover, the growing interest in the transition to circular economy models has shifted scientific focus toward plant-derived bioactive polypeptides. By investigating edible seed biochemistry, we have identified specific plant proteins that serve as precursors for polypeptide fragments with bioactivities comparable to those derived from less sustainable sources. This study investigates the structural and functional similarities of three major seed storage proteins: chenopodin[1] from quinoa (Chenopodium quinoa), beta-vignin[2] from cowpea (Vigna unguiculata), and glycinin[3] from soybean (Glycine max). We previously characterized their structural features and their potential to release bioactive sequences through enzymatic proteolysis. To improve sustainability of biomolecules production we aimed at overexpressing the aforementioned proteins/bioactive peptides in E. coli. However, since these proteins are of eukaryotic origin, they present significant technical bottlenecks: replicating the complex post-translational modifications essential for protein function, which are often absent or simplified in prokaryotic hosts, remains a major challenge. To address this, our experimental pipeline begins with bioinformatic structural prediction and modeling to map the "bioactive landscape" of the selected proteins, design optimized expression cassettes, and specific mutants. This phase is followed by high-level protein expression and targeted proteolysis. Preliminary data suggest that these overexpressed proteins can serve as efficient "bioreactors" for generating structural analogues, providing a scalable strategy for the next generation of bioactive polypeptides. [1] J. Capraro, S. De Benedetti, M. Di Dio, E. Bona, A. Abate, P. Corsetto, A. Scarafoni. Biomolecules (2020), 10, 795. [2] S. De Benedetti, C. Leogrande, F. Castagna, G.C. Heinzl, M. Pasquali, A.L. Heinzl, D. Lupi D., A. Scarafoni. Molecules (2022). 27, 277. [3] S. De Benedetti, V. Girlando, M. Pasquali, A. Scarafoni. Molecules (2021), 26, 4858.