SRPBCC domains have a deep hydrophobic ligand-binding pocket; they bind diverse ligands. Included in this superfamily are the steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domains of mammalian STARD1-STARD15, and the C-terminal catalytic domains of the alpha oxygenase subunit of Rieske-type non-heme iron aromatic ring-hydroxylating oxygenases (RHOs_alpha_C), as well as the SRPBCC domains of phosphatidylinositol transfer proteins (PITPs), Bet v 1 (the major pollen allergen of white birch, Betula verrucosa), CoxG, CalC, and related proteins. Other members of this superfamily include PYR/PYL/RCAR plant proteins, the aromatase/cyclase (ARO/CYC) domains of proteins such as Streptomyces glaucescens tetracenomycin, and the SRPBCC domains of Streptococcus mutans Smu.440 and related proteins.
Structure:1FM4_A; birch pollen allergen Bet V 1-L binds deoxycholic acid, contacts at 4A. - View structure with Cn3D
Comment:Bet v 1-L is believed to be involved in the transport of plant steroids. Although deoxycholate is not the natural ligand for Bet v 1, it is structurally very similar to the plant steroids, brassinosteroids.