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-FA BP) and heart (H-FABP) fatty acid-binding proteins were analyzed, in t he absence and in the presence of oleic acid, by Fourier transform ir spectroscopy. The study was done in order to gain information on the s econdary as well three-dimensional structure of L-FABP and to check th e 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 reve als that, in spite of the low sequence homology, the two proteins have similar secondary and probably tertiary structures. The ir data indic ates that a larger amount of beta-strands are exposed to the solvent i n H-FABP as compared to L-FABP, suggesting minor differences in the th ree-dimensional structures of these proteins. The binding of oleic aci d to L-FABP and H-FABP stabilized their structures and does not modify their secondary structure. The ir spectra neither confirm nor exclude self-association of human H-FABP. (C) 1995 John Wiley & Sons, Inc.