vulgaris (Kidney bean) and Petroselinum crispum (Parsley) (PR1-1 and PR1-3); the disease resistance response proteins, STH-2 and STH-21, from Solanum tuberosum (Potato) and pI49, pI176 and DRRG49-C from Pisum sativum (Garden pea); the P.sativum abscisic acid-responsive proteins ABR17 and ABR18; and the stress-induced protein SAM22 from Glycine max (Soybean). Additionally, the core domain of Bet v 1 founds or is part of a superfamily of domains called SRPBCC (START/RHOalphaC/PITP/Bet v1/CoxG/CalC) that include the StAR-related lipid-transfer (START) domain. Function The biological function of Bet v 1 is still under investigations. Bet v 1 harbors a large hydrophobic pocket and is able to bind a large spectra of ligands in it like hormones and siderophores like flavonols. It belongs to the pathogenesis-related (PR) proteins, which are usually expressed upon infections and stressful conditions, implicating a role in host defense. In vitro, Bet v 1 has been shown to be immune-suppressive, due to its ability to bind to iron-flavonoid complexes, which it can shuttle into human monocytic cells to increase their labile iron pool and stimulate the anti-inflammatory Arylhydrocarbon receptor pathway (https://www.mdpi.com/2076-3921/12/1/42). As such, only without any ligand, Bet v 1 was able to mount a Th2-response and turned into an allergen. References Allergology Protein families