Su-Ying Wu

β-lactoglobulin : Structural studies, biological clues

Bovine β-lactoglobulin (β-Lg) is a much studied and commercially important whey protein with an as yet undetermined function, although it is of obvious nutritional value. β-Lg binds a variety of ligands and by comparison of the general structures of these molecules together with several competition studies, it appears that there are at least 3 independent binding sites. In the absence of direct crystallographic evidence, a preliminary modelling study reveals that there is an internal cavity which can readily accommodate retinol in a manner similar to the related lipocalin, retinol-binding protein. On the outer surface, a solvent-accessible hydrophobic cleft runs between the 3-turn α-helix that is packed against the outer surface of the β-barrel. This cleft can accommodate fatty acids like palmitate and stearate. There is difference electron density observed in a soaking experiment with p-nitrophenol at a third site, on the outer surface close to the conserved Trp19/Arg124. This site is large enough to accommodate larger aromatic ligands such as ellipticine, although there is yet no independent evidence for this.

Milk protein structure - what can it tell the dairy industry?

This paper describes the possible usefulness of knowledge of the three-dimensional structure of milk proteins to dairy scientists. After a brief introduction of the available methodology and the structures of milk proteins that are already available, the structure of bovine β-lactoglobulin is used to illustrate the possible applications of the structure to understanding the problems to which the protein contributes during milk processing.