Protein-membrane interaction and ligand transfer to membranes from intestinal fatty acid binding proteins (FABPs) employing natural ligands
Protein-membrane interaction and ligand transfer to membranes from intestinal fatty acid binding proteins (FABPs) employing natural ligands
Liver and Intestinal fatty acid binding proteins (FABPs) 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. We employed two different methodologies: photocrosslinking studies and fluorescence-based FA transfer analysis employing natural ligands. The results of the photocrosslinking studies indicate that apo-IFABP interacts with membranes to a greater extent than holo-IFABP, while the opposite is observed for LFABP, probably indicating that IFABP could be delivering FA to membranes, whereas LFABP may be interacting to remove FA from membranes. Additionally, the interaction of IFABP is greatly increases with negatively charged vesicles, but is not affected by the charge in the vesicles for LFABP. 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.
S50-S50
Geronimo, Eduardo
98bf49b4-31a1-4b93-94a5-a3bb49806efb
Falomir-Lockhart, Lisandro.J.
5510f892-aae1-43be-9c64-6fa52bb9f0c4
Guerbi, María Ximena
f6bd97ed-d51c-465f-9a41-037f052f4759
Wilton, David.C.
4b995f66-ad6c-4d96-9179-c64f3b54466a
Corsico, Betina
25e47a9d-b01d-40b0-a71e-f95521e17533
September 2007
Geronimo, Eduardo
98bf49b4-31a1-4b93-94a5-a3bb49806efb
Falomir-Lockhart, Lisandro.J.
5510f892-aae1-43be-9c64-6fa52bb9f0c4
Guerbi, María Ximena
f6bd97ed-d51c-465f-9a41-037f052f4759
Wilton, David.C.
4b995f66-ad6c-4d96-9179-c64f3b54466a
Corsico, Betina
25e47a9d-b01d-40b0-a71e-f95521e17533
Geronimo, Eduardo, Falomir-Lockhart, Lisandro.J., Guerbi, María Ximena, Wilton, David.C. and Corsico, Betina
(2007)
Protein-membrane interaction and ligand transfer to membranes from intestinal fatty acid binding proteins (FABPs) employing natural ligands.
Chemistry and Physics of Lipids, 149 (1), .
(doi:10.1016/j.chemphyslip.2007.06.112).
Abstract
Liver and Intestinal fatty acid binding proteins (FABPs) 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. We employed two different methodologies: photocrosslinking studies and fluorescence-based FA transfer analysis employing natural ligands. The results of the photocrosslinking studies indicate that apo-IFABP interacts with membranes to a greater extent than holo-IFABP, while the opposite is observed for LFABP, probably indicating that IFABP could be delivering FA to membranes, whereas LFABP may be interacting to remove FA from membranes. Additionally, the interaction of IFABP is greatly increases with negatively charged vesicles, but is not affected by the charge in the vesicles for LFABP. 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.
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Published date: September 2007
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Local EPrints ID: 56699
URI: http://eprints.soton.ac.uk/id/eprint/56699
ISSN: 0009-3084
PURE UUID: ae19d20c-6d28-432b-a8e1-43e6a06063da
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Date deposited: 08 Aug 2008
Last modified: 15 Mar 2024 11:03
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Author:
Eduardo Geronimo
Author:
Lisandro.J. Falomir-Lockhart
Author:
María Ximena Guerbi
Author:
Betina Corsico
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