Rat liver fatty acid binding protein structure and function:The targeting of FABP-bound ligands to anionic interfaces
Rat liver fatty acid binding protein structure and function:The targeting of FABP-bound ligands to anionic interfaces
Liver fatty acid binding protein (LFABP) belongs to a family of small (14kDa) intracellular lipid-binding proteins, which have a characteristic β-barrel structure. The physiological role of FABP's within the cell remains unclear but a targeting role for the protein would provide an attractive mechanism for ligand (fatty acid) transfer to membrane sites for further metabolism and requires an interaction between the FABP and the membrane. In preliminary studies it was shown that LFABP released the fluorescent fatty acid 11(5-dimethylaminonapthalenesulphonylamino) undecanoic acid (DAUDA) in the presence of anionic phospholipid vesicles under conditions that indicated a direct interaction between the LFABP and the anionic phospholipid interface. This interaction was investigated in more detail in order to identify the parameters that affect binding and ligand release.
The ligand release that was observed with anionic vesicles was sensitive to the ionic strength of the assay conditions and the anionic charge density of the phospholipid at the interface, indicating that non-specific electrostatic interactions play an important role in the process. The stoichiometric relationship between anionic phospholipid and LFABP suggests that the LFABP coats the surface of the phosphilipid vesicle. The most likely explanation for ligand release is that interaction of LFABF with an anionic membrane interface induces a rapid conformational change, reducing the affinity of DAUDA for the protein. The nature of this interaction involves both electrostatic and non-polar interactions as maximal release of LFABP from phospholipid vesicles with recovery of ligand binding cannot be achieved with high salt and requires the presence of a non-anionic detergent.
Lysine residues in the α-helical region of adipocyte and heart FABP had previously been identified as important for interactions between these proteins and the phospholipid interface. Therefore, the charge reversal mutant, K20E, K31E and K33E of the α-helical regions of LFABP were produced and investigated. The results of these studies suggested that α-helix II, in particular, residue K31 of LFABP are involved in interactions with the anionic phospholipid interface.
University of Southampton
Davies, Joanna Kay
5fbf6b0d-0604-46ef-8ccd-ccdbe5b58ad9
2001
Davies, Joanna Kay
5fbf6b0d-0604-46ef-8ccd-ccdbe5b58ad9
Davies, Joanna Kay
(2001)
Rat liver fatty acid binding protein structure and function:The targeting of FABP-bound ligands to anionic interfaces.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Liver fatty acid binding protein (LFABP) belongs to a family of small (14kDa) intracellular lipid-binding proteins, which have a characteristic β-barrel structure. The physiological role of FABP's within the cell remains unclear but a targeting role for the protein would provide an attractive mechanism for ligand (fatty acid) transfer to membrane sites for further metabolism and requires an interaction between the FABP and the membrane. In preliminary studies it was shown that LFABP released the fluorescent fatty acid 11(5-dimethylaminonapthalenesulphonylamino) undecanoic acid (DAUDA) in the presence of anionic phospholipid vesicles under conditions that indicated a direct interaction between the LFABP and the anionic phospholipid interface. This interaction was investigated in more detail in order to identify the parameters that affect binding and ligand release.
The ligand release that was observed with anionic vesicles was sensitive to the ionic strength of the assay conditions and the anionic charge density of the phospholipid at the interface, indicating that non-specific electrostatic interactions play an important role in the process. The stoichiometric relationship between anionic phospholipid and LFABP suggests that the LFABP coats the surface of the phosphilipid vesicle. The most likely explanation for ligand release is that interaction of LFABF with an anionic membrane interface induces a rapid conformational change, reducing the affinity of DAUDA for the protein. The nature of this interaction involves both electrostatic and non-polar interactions as maximal release of LFABP from phospholipid vesicles with recovery of ligand binding cannot be achieved with high salt and requires the presence of a non-anionic detergent.
Lysine residues in the α-helical region of adipocyte and heart FABP had previously been identified as important for interactions between these proteins and the phospholipid interface. Therefore, the charge reversal mutant, K20E, K31E and K33E of the α-helical regions of LFABP were produced and investigated. The results of these studies suggested that α-helix II, in particular, residue K31 of LFABP are involved in interactions with the anionic phospholipid interface.
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Published date: 2001
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Local EPrints ID: 464602
URI: http://eprints.soton.ac.uk/id/eprint/464602
PURE UUID: 8f3729fa-9583-4a6c-9926-16881128af43
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Date deposited: 04 Jul 2022 23:50
Last modified: 16 Mar 2024 19:38
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Author:
Joanna Kay Davies
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