β-Conglutins' Unique Mobile Arm Is a Key Structural Domain Involved in Molecular Nutraceutical Properties of Narrow-Leafed Lupin (Lupinus angustifolius L.)

Narrow-leafed lupin (NLL; Lupinus angustifolius L.) has multiple nutraceutical properties that may result from unique structural features of beta-conglutin proteins, such as the mobile arm at the N-terminal, a structural domain rich in alpha-helices. A similar domain has not been found in other vicilin proteins of legume species. We used affinity chromatography to purify recombinant complete and truncated (without the mobile arm domain, t beta 5 and t beta 7) forms of NLL beta 5 and beta 7 conglutin proteins. We then used biochemical and molecular biology techniques in ex vivo and in vitro systems to evaluate their anti-inflammatory activity and antioxidant capacity. The complete beta 5 and beta 7 conglutin proteins decreased pro-inflammatory mediator levels (e.g., nitric oxide), mRNA expression levels (iNOS, TNF alpha, IL-1 beta), and the protein levels of pro-inflammatory cytokine TNF-alpha, interleukins (IL-1 beta, IL-2, IL-6, IL-8, IL-12, IL-17, IL-27), and other mediators (INF gamma, MOP, S-TNF-R1/-R2, and TWEAK), and exerted a regulatory oxidative balance effect in cells as demonstrated in glutathione, catalase, and superoxide dismutase assays. The truncated t beta 5 and t beta 7 conglutin proteins did not have these molecular effects. These results suggest that beta 5 and beta 7 conglutins have potential as functional food components due to their anti-inflammatory and oxidative cell state regulatory properties, and that the mobile arm of NLL beta-conglutin proteins is a key domain in the development of nutraceutical properties, making NLL beta 5 and beta 7 excellent innovative candidates as functional foods.

Automated summary

Narrow-leafed lupin (NLL) beta-5 and beta-7 conglutin proteins, containing unique structural features like the mobile arm at the N-terminal, showed anti-inflammatory and oxidative cell state regulatory properties, reducing pro-inflammatory mediators and cytokines. Truncated forms of these proteins did not exhibit the same effects. This suggests that the mobile arm domain is key in developing nutraceutical properties, making NLL beta-5 and beta-7 potential functional food components.