ABSTRACT
Introduction The lipocalin protein family consists mainly of small extracellular proteins that bind hydro-
phobic ligands and fulfill numerous biological functions including ligand transport, cryptic col oration, sensory transduction, the biosynthesis of prostaglandins, and the regulation of cellular homeostasis and immunity. The lipocalins can be structurally characterized as an 8-stranded antiparallel β-barrel followed by a C-terminal α-helix, as exemplified by serum retinol binding protein.1 The lipocalin fold is widely distributed among vertebrates and a few have been isolated from invertebrates and plants. Until 1995, when the first bacterial lipocalins were identified,2 the
Lipocalins, edited by Bo Akerstrom, Niels Borregaard, Darren R. Flower and Jean-Philippe Salier. ©2006 Landes Bioscience.
