7S vicilin seed storage globulin, N-terminal cupin domain
This family contains the N-terminal domains of plant 7S seed storage proteins such as vicilin, and includes beta-conglycinin, phaseolin, canavalin, conglutin-beta, a chromatin protein in Pisum sativum called P54, and a sucrose binding protein in soybean called SBP. These 7S globulins also include soybean allergen beta-conglycinin, peanut allergen conarachin (Ara h 1), walnut allergen Jug r 2, and lentil allergen Len c 1. Proteins in this family perform various functions, including a role in sucrose binding, desiccation, defense against microbes and oxidative stress. The vicilin peptides formed by trypsin or chymotrypsin digestion exhibit antihypertensive effects. These plant seed storage globulins have tandem cupin-like beta-barrel folds (referred to as a bicupin). Storage proteins are the cause of well-known allergic reactions to peanuts and cereals. Proteins in this family belong to the cupin superfamily with a conserved "jelly roll-like" beta-barrel fold.