InterPro: IPR000677 2S globulin

All legume seeds contain storage globulins, a family of proteins of different size and structural organisation that share several properties (including similar amino acid composition, salting-in solubility, etc.). The globulins are generally classified with respect to their molecular mass as 2S, 7S (vicilin) or 11S (legumin). Narbonin belongs to the smaller, 2S globulins. It is a monomer of 290 amino acid residues and consists of a single polypeptide chain. Narbonin folds as an beta/alpha-protein, with strands and helices alternating to form an 8-stranded parallel beta-barrel surrounded by a ring of 7 helices [1, 2], the familiar topology of triose phosphate isomerase and many other enzymes. To date, attempts to identify an enzymatic activity for this protein, however, have failed [1].