The Lipocalin Protein Family: Protein Sequence, Structure and Relationship to the Calycin Superfamily

Abstract

Lipocalins are remarkable in their diversity, as manifest at the levels of protein sequence and protein function. At the level of 3-dimensional structure, however, they are very similar. The lipocalins are also part of a larger protein superfamily: the calycins, which also includes the fatty acid binding proteins, adivins, a group of metalloproteinase inhibitors, and triabin. The superfamily is characterised by a similar structure (a repeated +1 topology B-barrel) and by the conservation of a remarkable structural signature. In this review, both of these aspects are explored.