Liver fatty acid binding protein: species variation and the accommodation of different ligands

The crystal structure of rat liver fatty acid binding protein (LFABP) and a n alignment of amino acid sequences of all known species have been used to demonstrate two groups or sub-classes. Based on estimates at neutral pH and the electrostatic field calculated using the crystal coordinates, some evi dence of changes that occur in going from holo- to apo-forms has been obtai ned. LFABP belongs to a large family frequently referred to as the intracel lular lipid binding proteins or iLBPs. LFABP, unlike other family members, has two fatty acid binding sites. The two cavity sites have been reviewed a nd arguments for interactions between the sites are presented. Based on the crystal structure of rat LFABP, differences between the A and B groups hav e been postulated. Last of all, hypothetical models have been built of comp lexes of LFABP and heme, and LFABP and oleoyl CoA. In both cases, the stoic hiometry is one to one and the models show why this is likely. (C) 1999 Els evier Science B.V. All rights reserved.