title: Chlamydomonas carries out fatty acid β-oxidation in ancestral peroxisomes using a bona fide acyl-CoA oxidase.
abstract: Peroxisomes are thought to have played a key role in the evolution of metabolic networks of photosynthetic organisms by connecting oxidative and biosynthetic routes operating in different compartments. While the various oxidative pathways operating in the peroxisomes of higher plants are fairly well characterized, the reactions present in the primitive peroxisomes (microbodies) of algae are poorly understood. Screening of a Chlamydomonas insertional mutant library identified a strain strongly impaired in oil remobilization and defective in Cre05.g232002 (CrACX2), a gene encoding a member of the acyl-CoA oxidase/dehydrogenase superfamily. The purified recombinant CrACX2 expressed in Escherichia coli catalyzed the oxidation of fatty acyl-CoAs into trans-2-enoyl-CoA and produced H2O2. This result demonstrated that CrACX2 is a genuine acyl-CoA oxidase, which is responsible for the first step of the peroxisomal fatty acid (FA) β-oxidation spiral. A fluorescent protein-tagging study pointed to a peroxisomal location of CrACX2. The importance of peroxisomal FA β-oxidation in algal physiology was shown by the impact of the mutation on FA turnover during day/night cycles. Moreover, under nitrogen depletion the mutant accumulated 20% more oil than the wild type, illustrating the potential of β-oxidation mutants for algal biotechnology. This study provides experimental evidence that a plant-type FA β-oxidation involving H2O2-producing acyl-CoA oxidation activity has already evolved in the microbodies of the unicellular green alga Chlamydomonas reinhardtii.
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, CNRS, Aix Marseille Université, UMR7265, Institut de Biosciences et Biotechnologies Aix Marseille, 13108, Cadarache, France.
authors.forename: Fantao
authors.initials: F
authors.lastname: Kong
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, CNRS, Aix Marseille Université, UMR7265, Institut de Biosciences et Biotechnologies Aix Marseille, 13108, Cadarache, France.
authors.forename: Yuanxue
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, CNRS, Aix Marseille Université, UMR7265, Institut de Biosciences et Biotechnologies Aix Marseille, 13108, Cadarache, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Légeret
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, CNRS, Aix Marseille Université, UMR7265, Institut de Biosciences et Biotechnologies Aix Marseille, 13108, Cadarache, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Beyly-Adriano
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, CNRS, Aix Marseille Université, UMR7265, Institut de Biosciences et Biotechnologies Aix Marseille, 13108, Cadarache, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Blangy
authors.affiliation: Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, UK.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Haslam
authors.affiliation: Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, UK.
authors.forename: Johnathan A
authors.initials: JA
authors.lastname: Napier
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, CNRS, Aix Marseille Université, UMR7265, Institut de Biosciences et Biotechnologies Aix Marseille, 13108, Cadarache, France.
authors.forename: Fred
authors.initials: F
authors.lastname: Beisson
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, CNRS, Aix Marseille Université, UMR7265, Institut de Biosciences et Biotechnologies Aix Marseille, 13108, Cadarache, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Peltier
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives, CNRS, Aix Marseille Université, UMR7265, Institut de Biosciences et Biotechnologies Aix Marseille, 13108, Cadarache, France.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Li-Beisson
mesh_terms: D042962:Acyl-CoA Oxidase / Q000378:metabolism*; D002696:Chlamydomonas / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D050356:Lipid Metabolism / Q000235:genetics / Q000502:physiology; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D020675:Peroxisomes / Q000378:metabolism*
chemical_list: D006861:Hydrogen Peroxide; D042962:Acyl-CoA Oxidase; D009584:Nitrogen
keywords: 
  Chlamydomonas reinhardtii
  ; acyl-CoA oxidase; catalase; hydrogen peroxide; lipid catabolism; lipid droplet; lipid homeostasis; microbodies; nitrogen starvation; oil content