title: Interaction kinetics of liposome-incorporated unsaturated fatty acids with fatty acid-binding protein 3 by surface plasmon resonance.
abstract: The role of heart-type fatty acid-binding protein (FABP3) in human physiology as an intracellular carrier of fatty acids (FAs) has been well-documented. In this study, we aimed to develop an analytical method to study real-time interaction kinetics between FABP3 immobilized on the sensor surface and unsaturated C18 FAs using surface plasmon resonance (SPR). To establish the conditions for SPR experiments, we used an FABP3-selective inhibitor 4-(2-(1-(4-bromophenyl)-5-phenyl-1H-pyrazol-3-yl)-phenoxy)-butyric acid. The affinity index thus obtained was comparable to that reported previously, further supporting the usefulness of the SPR-based approach for evaluating interactions between FABPs and hydrophobic ligands. A pseudo-first-order affinity of FABP3 to K(+) petroselinate (C18:1 Δ6 cis), K(+) elaidate (C18:1 Δ9 trans), and K(+) oleate (C18:1 Δ9 cis) was characterized by the dissociation constant (K(d)) near micromolar ranges, whereas K(+) linoleate (C18:2 Δ9,12 cis/cis) and K(+) α-linolenate (C18:3 Δ9,12,15 cis/cis/cis) showed a higher affinity to FABP3 with Kd around 1 × 10(-6)M. Interactions between FAPB3 and C18 FAs incorporated in large unilamellar vesicles consisting of 1,2-dimyristoyl-sn-glycero-3-phosphocholine and FAs (5:1 molar ratio) were also analysed. Control DMPC liposomes without FA showed only marginal binding to FABP3 immobilized on a sensor chip while liposome-incorporated FA revealed significant responses in sensorgrams, demonstrating that the affinity of FAs to FABP3 could be evaluated by using the liposome-incorporated analytes. Significant affinity to FABP3 was observed for monounsaturated fatty acids (K(d) in the range of 1 × 10(-7)M). These experiments demonstrated that highly hydrophobic compounds in a liposome-incorporated form could be subjected to SPR experiments for kinetic analysis.
authors.affiliation: JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, De La Salle University, 2401 Taft Avenue, Malate, Manila 1004, Philippines.
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: Tan
authors.affiliation: JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Project Research Center for Fundamental Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Matsuoka
authors.affiliation: JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Project Research Center for Fundamental Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Hikaru
authors.initials: H
authors.lastname: Ano
authors.affiliation: JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Hanako
authors.initials: H
authors.lastname: Ishida
authors.affiliation: JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Hirose
authors.affiliation: JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Project Research Center for Fundamental Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Sato
authors.affiliation: JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Sugiyama
authors.affiliation: JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Project Research Center for Fundamental Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan. Electronic address: murata@chem.sci.osaka-u.ac.jp.
authors.forename: Michio
authors.initials: M
authors.lastname: Murata
mesh_terms: D000074026:Fatty Acid Binding Protein 3; D050556:Fatty Acid-Binding Proteins / Q000737:chemistry* / Q000235:genetics; D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D008081:Liposomes / Q000138:chemical synthesis / Q000737:chemistry*; D020349:Surface Plasmon Resonance
chemical_list: C493408:FABP3 protein, human; D000074026:Fatty Acid Binding Protein 3; D050556:Fatty Acid-Binding Proteins; D005231:Fatty Acids, Unsaturated; D008081:Liposomes
keywords: Fatty acid binding proteins; Large unilamellar vesicles; Surface plasmon resonance