title: Binding of 18-carbon unsaturated fatty acids to bovine β-lactoglobulin--structural and thermodynamic studies.
abstract: Binding of 18-carbon unsaturated oleic and linoleic acid to lactoglobulin, the milk protein, has been studied for the first time by isothermal titration calorimetry (ITC) and X-ray crystallography. Crystal structures determined to resolution 2.10 Å have revealed presence of single fatty acid molecule bound in β-barrel, the primary binding site, with carboxyl group hydrogen bonded to Glu62. The aliphatic chain of both ligands is in almost linear conformation and their interactions with the protein are similar to observed in structure of lactoglobulin with stearic acid. The ITC experiments showed that binding of unsaturated fatty acids to LGB is spontaneous and exothermic. The stoichiometry of binding is lower than 1.0, association constant is 9.7 × 10(5)M(-1) and 9.0 × 10(5)M(-1) for oleic and linoleic acid, respectively. Solvent relief seems to be the major contributor to entropic changes upon fatty acid binding to lactoglobulin.
authors.affiliation: Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland.
authors.forename: Joanna I
authors.initials: JI
authors.lastname: Loch
authors.forename: Piotr
authors.initials: P
authors.lastname: Bonarek
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Polit
authors.forename: Delphine
authors.initials: D
authors.lastname: Riès
authors.forename: Marta
authors.initials: M
authors.lastname: Dziedzicka-Wasylewska
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Lewiński
mesh_terms: D000818:Animals; D001665:Binding Sites; D002417:Cattle; D007782:Lactoglobulins / Q000737:chemistry* / Q000378:metabolism; D019301:Oleic Acid / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
chemical_list: D007782:Lactoglobulins; D019301:Oleic Acid