Document Detail


Protein-membrane interaction and fatty acid transfer from intestinal fatty acid-binding protein to membranes. Support for a multistep process.
MedLine Citation:
PMID:  16551626     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Fatty acid transfer from intestinal fatty acid-binding protein (IFABP) to phospholipid membranes occurs during protein-membrane collisions. Electrostatic interactions involving the alpha-helical "portal" region of the protein have been shown to be of great importance. In the present study, the role of specific lysine residues in the alpha-helical region of IFABP was directly examined. A series of point mutants in rat IFABP was engineered in which the lysine positive charges in this domain were eliminated or reversed. Using a fluorescence resonance energy transfer assay, we analyzed the rates and mechanism of fatty acid transfer from wild type and mutant proteins to acceptor membranes. Most of the alpha-helical domain mutants showed slower absolute fatty acid transfer rates to zwitterionic membranes, with substitution of one of the lysines of the alpha2 helix, Lys27, resulting in a particularly dramatic decrease in the fatty acid transfer rate. Sensitivity to negatively charged phospholipid membranes was also reduced, with charge reversal mutants in the alpha2 helix the most affected. The results support the hypothesis that the portal region undergoes a conformational change during protein-membrane interaction, which leads to release of the bound fatty acid to the membrane and that the alpha2 segment is of particular importance in the establishment of charge-charge interactions between IFABP and membranes. Cross-linking experiments with a phospholipid-photoactivable reagent underscored the importance of charge-charge interactions, showing that the physical interaction between wild-type intestinal fatty acid-binding protein and phospholipid membranes is enhanced by electrostatic interactions. Protein-membrane interactions were also found to be enhanced by the presence of ligand, suggesting different collisional complex structures for holo- and apo-IFABP.
Authors:
Lisandro J Falomir-Lockhart; Lisandro Laborde; Peter C Kahn; Judith Storch; Betina Córsico
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2006-03-21
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  281     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2006 May 
Date Detail:
Created Date:  2006-05-15     Completed Date:  2006-07-21     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  13979-89     Citation Subset:  IM    
Affiliation:
Instituto de Investigaciones Bioquímicas de La Plata, CONICET-UNLP, Facultad de Ciencias Médicas, Calles 60 y 120, 1900-La Plata, Argentina.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Membrane / metabolism*
Cross-Linking Reagents / pharmacology
Fatty Acid-Binding Proteins / metabolism*
Fatty Acids / metabolism*
Fluorescence Resonance Energy Transfer
Models, Molecular
Mutation
Protein Binding
Protein Structure, Secondary
Protein Structure, Tertiary
Rats
Static Electricity
Grant Support
ID/Acronym/Agency:
DK 38389/DK/NIDDK NIH HHS; TW01100-01/TW/FIC NIH HHS
Chemical
Reg. No./Substance:
0/Cross-Linking Reagents; 0/Fatty Acid-Binding Proteins; 0/Fatty Acids

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