title: The Mycobacterium tuberculosis very-long-chain fatty acyl-CoA synthetase: structural basis for housing lipid substrates longer than the enzyme.
abstract: The Mycobacterium tuberculosis acid-induced operon MymA encodes the fatty acyl-CoA synthetase FadD13 and is essential for virulence and intracellular growth of the pathogen. Fatty acyl-CoA synthetases activate lipids before entering into the metabolic pathways and are also involved in transmembrane lipid transport. Unlike soluble fatty acyl-CoA synthetases, but like the mammalian integral-membrane very-long-chain acyl-CoA synthetases, FadD13 accepts lipid substrates up to the maximum length tested (C(26)). Here, we show that FadD13 is a peripheral membrane protein. The structure and mutational studies reveal an arginine- and aromatic-rich surface patch as the site for membrane interaction. The protein accommodates a hydrophobic tunnel that extends from the active site toward the positive patch and is sealed by an arginine-rich lid-loop at the protein surface. Based on this and previous data, we propose a structural basis for accommodation of lipid substrates longer than the enzyme and transmembrane lipid transport by vectorial CoA-esterification.
authors.affiliation: Stockholm Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences C4, SE-10691 Stockholm, Sweden.
authors.forename: Charlotta S
authors.initials: CS
authors.lastname: Andersson
authors.forename: Camilla A K
authors.initials: CA
authors.lastname: Lundgren
authors.forename: Auður
authors.initials: A
authors.lastname: Magnúsdóttir
authors.forename: Changrong
authors.initials: C
authors.lastname: Ge
authors.forename: Ake
authors.initials: A
authors.lastname: Wieslander
authors.forename: Daniel
authors.initials: D
authors.lastname: Martinez Molina
authors.forename: Martin
authors.initials: M
authors.lastname: Högbom
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000302:isolation & purification; D020134:Catalytic Domain; D003066:Coenzyme A Ligases / Q000737:chemistry* / Q000302:isolation & purification; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D013499:Surface Properties
chemical_list: D001425:Bacterial Outer Membrane Proteins; D003066:Coenzyme A Ligases