title: Structural characterization of acyl-CoA oxidases reveals a direct link between pheromone biosynthesis and metabolic state in Caenorhabditis elegans.
abstract: Caenorhabditis elegans secretes ascarosides as pheromones to communicate with other worms and to coordinate the development and behavior of the population. Peroxisomal β-oxidation cycles shorten the side chains of ascaroside precursors to produce the short-chain ascaroside pheromones. Acyl-CoA oxidases, which catalyze the first step in these β-oxidation cycles, have different side chain-length specificities and enable C. elegans to regulate the production of specific ascaroside pheromones. Here, we determine the crystal structure of the acyl-CoA oxidase 1 (ACOX-1) homodimer and the ACOX-2 homodimer bound to its substrate. Our results provide a molecular basis for the substrate specificities of the acyl-CoA oxidases and reveal why some of these enzymes have a very broad substrate range, whereas others are quite specific. Our results also enable predictions to be made for the roles of uncharacterized acyl-CoA oxidases in C. elegans and in other nematode species. Remarkably, we show that most of the C. elegans acyl-CoA oxidases that participate in ascaroside biosynthesis contain a conserved ATP-binding pocket that lies at the dimer interface, and we identify key residues in this binding pocket. ATP binding induces a structural change that is associated with tighter binding of the FAD cofactor. Mutations that disrupt ATP binding reduce FAD binding and reduce enzyme activity. Thus, ATP may serve as a regulator of acyl-CoA oxidase activity, thereby directly linking ascaroside biosynthesis to ATP concentration and metabolic state.
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611.
authors.forename: Xinxing
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611.
authors.forename: Kunhua
authors.identifier: 0000-0002-9139-4257
authors.initials: K
authors.lastname: Li
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Jones
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Bruner
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL 32611 butcher@chem.ufl.edu.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Butcher
mesh_terms: D042962:Acyl-CoA Oxidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D017173:Caenorhabditis elegans / Q000737:chemistry* / Q000201:enzymology; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry / Q000378:metabolism; D015870:Gene Expression; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D009154:Mutation; D010084:Oxidation-Reduction; D010675:Pheromones / Q000096:biosynthesis / Q000737:chemistry*; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D000072757:Protein Conformation, beta-Strand; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity
chemical_list: D029742:Caenorhabditis elegans Proteins; D007527:Isoenzymes; D010675:Pheromones; D011994:Recombinant Proteins; D005182:Flavin-Adenine Dinucleotide; D000255:Adenosine Triphosphate; D042962:Acyl-CoA Oxidase
keywords: ATP; ascarosides; beta-oxidation; crystal structure; dauer pheromone