Structural properties and thermal stability of human liver and heart fatty acid binding proteins: A fourier transform IR spectroscopy study

The secondary structure and the thermal stability of human liver (L‐FARP) and heart (77‐FAUP) fatty acid‐binding proteins were analyzed, in the absence and in the presence of oleic acid, by Fourier transform ir spectroscopv. The study was done in order to gain information on the secondary us well three‐dimensional structure of L.‐FARP and to check the possible H‐FABP self‐association that has been found to occur in rat and pig H‐FABP. Comparison of human L‐FABP and H‐FABP ir spectra reveals that, in spite of the low sequencehomology, the two proteins have similar secondary and probably tertiary structures. The air data indicates that a larger amount of β‐strands are exposed to the solvent in H‐FABP as compared to L‐FABP, suggesting mi nordifferences in the three‐dimensional structures of these proteins. The binding of oleic acid to L‐FABP and H‐FABP stabilizes their structures and does not modify their secondary structure. Their spectra neither confirm nor exclude self‐association of human H‐FABP. © 1995 John Wiley & Sons, Inc.