Characterization of a small acyl-CoA-binding protein (ACBP) from Helianthus annuus L. and its binding affinities

• Published in: Plant physiology and biochemistry Vol. 102; pp. 141 - 150
• Main Authors: Aznar-Moreno, Jose A., Venegas-Calerón, Mónica, Du, Zhi-Yan, Garcés, Rafael, Tanner, Julian A., Chye, Mee-Len, Martínez-Force, Enrique, Salas, Joaquín J.
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.05.2016
• Subjects: acyl coenzyme A; Acyl Coenzyme A - chemistry; Acyl Coenzyme A - metabolism; Acyl-CoA; Acyl-CoA binding protein; Arabidopsis thaliana; binding capacity; Brassica napus; calorimetry; Carrier Proteins - biosynthesis; Carrier Proteins - chemistry; Carrier Proteins - genetics; cell structures; esters; Gene Expression Regulation, Plant - physiology; Helianthus - chemistry; Helianthus - genetics; Helianthus - metabolism; Helianthus annuus; Oryza sativa; Phosphatidic acid; Phosphatidylcholine; phosphatidylcholines; Phospholipids; Plant Proteins - biosynthesis; Plant Proteins - chemistry; Plant Proteins - genetics; Protein Binding; Sunflower; sunflower oil; sunflower seed protein; tissues; titration; Phosphatidylcholine; Acyl-CoA; Acyl-CoA binding protein; Phospholipids; Sunflower; Phosphatidic acid
• ISSN: 0981-9428; 1873-2690; 1873-2690
• DOI: 10.1016/j.plaphy.2016.02.025

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. •A class I acyl CoA binding protein from sunflower that is called HaACBP6 was cloned.•HaACBP6 is expressed ubiquitously in all sunflower organs.•HaACBP6 displays lower affinity for 18:2-CoA than for other acyl-CoA derivatives.•HaACBP6 binds to phosphatidyl choline but not to phosphatidate or lysophospholipids.•HACBP6 is located in the cytosol.