title: Characterization of a small acyl-CoA-binding protein (ACBP) from Helianthus annuus L. and its binding affinities.
abstract: Acyl-CoA-binding proteins (ACBPs) bind to acyl-CoA esters and promote their interaction with other proteins, lipids and cell structures. Small class I ACBPs have been identified in different plants, such as Arabidopsis thaliana (AtACBP6), Brassica napus (BnACBP) and Oryza sativa (OsACBP1, OsACBP2, OsACBP3), and they are capable of binding to different acyl-CoA esters and phospholipids. Here we characterize HaACBP6, a class I ACBP expressed in sunflower (Helianthus annuus) tissues, studying the specificity of its corresponding recombinant HaACBP6 protein towards various acyl-CoA esters and phospholipids in vitro, particularly using isothermal titration calorimetry and protein phospholipid binding assays. This protein binds with high affinity to de novo synthetized derivatives palmitoly-CoA, stearoyl-CoA and oleoyl-CoA (Kd 0.29, 0.14 and 0.15 μM respectively). On the contrary, it showed lower affinity towards linoleoyl-CoA (Kd 5.6 μM). Moreover, rHaACBP6 binds to different phosphatidylcholine species (dipalmitoyl-PC, dioleoyl-PC and dilinoleoyl-PC), yet it displays no affinity towards other phospholipids like lyso-PC, phosphatidic acid and lysophosphatidic acid derivatives. In the light of these results, the possible involvement of this protein in sunflower oil synthesis is considered.
authors.affiliation: Department of Biochemistry & Molecular Biophysics, Kansas State University, 141 Chalmers Hall, Manhattan, KS 66506.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Aznar-Moreno
authors.affiliation: Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Ctra. de Utrera Km 1, 41013 Seville, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Venegas-Calerón
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Zhi-Yan
authors.initials: ZY
authors.lastname: Du
authors.affiliation: Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Ctra. de Utrera Km 1, 41013 Seville, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Garcés
authors.affiliation: Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Julian A
authors.initials: JA
authors.lastname: Tanner
authors.affiliation: School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong.
authors.forename: Mee-Len
authors.initials: ML
authors.lastname: Chye
authors.affiliation: Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Ctra. de Utrera Km 1, 41013 Seville, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Martínez-Force
authors.affiliation: Instituto de la Grasa (CSIC), Campus Universitario Pablo de Olavide, Ctra. de Utrera Km 1, 41013 Seville, Spain. Electronic address: jjsalas@ig.csic.es.
authors.forename: Joaquín J
authors.initials: JJ
authors.lastname: Salas
mesh_terms: D000214:Acyl Coenzyme A / Q000737:chemistry / Q000378:metabolism; D002352:Carrier Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D006368:Helianthus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D011485:Protein Binding
chemical_list: D000214:Acyl Coenzyme A; D002352:Carrier Proteins; D010940:Plant Proteins
keywords: Acyl-CoA; Acyl-CoA binding protein; Phosphatidic acid; Phosphatidylcholine; Phospholipids; Sunflower