Liver fatty acid binding protein (LFABP) transfers fatty acids and fatty acyl-CoAs to membranes

EDUARDO DE GERÓNIMO; ROBERT M. HAGAN; DAVID C. WILTON; BETINA CÓRSICO

Maastricht

Congreso; 49th International Conference on the Bioscience of Lipids; 2008

International Conference on the Bioscience of Lipids

Liver fatty acid binding proteins (LFABPs) are small cytosolic proteins presumably involved in the uptake and targeting of fatty acids (FA) to intracellular organelles and metabolic pathways. All further sites of metabolism of long chain FA involve membrane proteins. The objective of this work was to analyze FABP-membrane interaction and FA transfer from FABPs to artificial membranes, in order to better understand the specific physiological roles of I- and LFABP in the enterocyte. To deepen our understanding of the LFABP FA targeting role, we have employed a tryptophan containing mutant at position 28 (L28W), whose fluorescence is enhanced upon FA binding. This gives us the chance to study both the ligand-protein interaction and protein-to-membrane ligand transfer using various physiological ligands instead of the analogues we have been employing previously. So far, our results of the binding properties of the L28W mutant with oleic acid, under physiological ionic strength, are consistent with a 2 site cooperative mechanism. We have also analyzed the transfer of oleic acid from L28W to phosphatidylcholine vesicles which showed that L28W will let us perform kinetic studies of FA transfer from protein to membranes under conditions which are closer to the physiological, and hence further our knowledge of the specific function/s of LFABP.