The lipocalins are a family of proteins which transport small hydrophobic molecules such as steroids, bilins, retinoids, and lipids, and most lipocalins are also able to bind to complexed iron (via siderophores[2] or flavonoids[3]) as well as heme.[4] They share limited regions of sequence homology and a common tertiary structure architecture.[5][6][7][8][9] This is an eight stranded antiparallel beta barrel with a repeated + 1 topology enclosing an internal ligand binding site.[7][8]
^ abCowan SW, Newcomer ME, Jones TA (1990). "Crystallographic refinement of human serum retinol binding protein at 2A resolution". Proteins. 8 (1): 44–61. doi:10.1002/prot.340080108. PMID2217163. S2CID21613341.
^Godovac-Zimmermann J (February 1988). "The structural motif of beta-lactoglobulin and retinol-binding protein: a basic framework for binding and transport of small hydrophobic molecules?". Trends in Biochemical Sciences. 13 (2): 64–66. doi:10.1016/0968-0004(88)90031-X. PMID3238752.