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Publication Abstract from PubMed

Fatty acid-binding proteins (FABPs) are involved in transporting hydrophobic fatty acids between various aqueous compartments of the cell by directly binding ligands inside their beta-barrel cavities. Here, we report the crystal structures of ligand-unbound pFABP4, linoleate-bound pFABP4, and palmitate-bound pFABP5, obtained from gentoo penguin (Pygoscelis papua), at a resolution of 2.1 A, 2.2 A, and 2.3 A, respectively. The pFABP4 and pFABP5 proteins have a canonical beta-barrel structure with two short alpha-helices that form a cap region and fatty acid ligand binding sites in the hydrophobic cavity within the beta-barrel structure. Linoleate-bound pFABP4 and palmitate-bound pFABP5 possess different ligand-binding modes and a unique ligand-binding pocket due to several sequence dissimilarities (A76/L78, T30/M32, underlining indicates pFABP4 residues) between the two proteins. Structural comparison revealed significantly different conformational changes in the beta3-beta4 loop region (residues 57-62) as well as the flipped Phe60 residue of pFABP5 than that in pFABP4 (the corresponding residue is Phe58). A ligand-binding study using fluorophore displacement assays shows that pFABP4 has a relatively strong affinity for linoleate as compared to pFABP5. In contrast, pFABP5 exhibits higher affinity for palmitate than that for pFABP4. In conclusion, our high-resolution structures and ligand-binding studies provide useful insights into the ligand-binding preferences of pFABPs based on key protein-ligand interactions.

Structural basis for the ligand-binding specificity of fatty acid-binding proteins (pFABP4 and pFABP5) in gentoo penguin.,Lee CW, Kim JE, Do H, Kim RO, Lee SG, Park HH, Chang JH, Yim JH, Park H, Kim IC, Lee JH Biochem Biophys Res Commun. 2015 Jul 20. pii: S0006-291X(15)30317-X. doi:, 10.1016/j.bbrc.2015.07.087. PMID:26206084^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.