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New insight into the photoheterotrophic growth of the isocytrate lyase-lacking purple bacterium Rhodospirillum rubrum on acetate.
Leroy, B; De Meur, Q; Moulin, C; Wegria, G; Wattiez, R.
Afiliación
  • Leroy B; Laboratory of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons, Place du Parc 20, 7000 Mons, Belgium.
  • De Meur Q; Laboratory of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons, Place du Parc 20, 7000 Mons, Belgium.
  • Moulin C; Laboratory of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons, Place du Parc 20, 7000 Mons, Belgium.
  • Wegria G; Biotech Materia Nova, Parc Initialis, Avenue Copernic 1, 7000 Mons, Belgium.
  • Wattiez R; Laboratory of Proteomics and Microbiology, Research Institute for Biosciences, University of Mons, Place du Parc 20, 7000 Mons, Belgium.
Microbiology (Reading) ; 161(Pt 5): 1061-1072, 2015 May.
Article en En | MEDLINE | ID: mdl-25737481
Purple non-sulfur bacteria are well known for their metabolic versatility. One of these bacteria, Rhodospirillum rubrum S1H, has been selected by the European Space Agency to ensure the photoheterotrophic assimilation of volatile fatty acids in its regenerative life support system, MELiSSA. Here, we combined proteomic analysis with bacterial growth analysis and enzymatic activity assays in order to better understand acetate photoassimilation. In this isocitrate lyase-lacking organism, the assimilation of two-carbon compounds cannot occur through the glyoxylate shunt, and the citramalate cycle has been proposed to fill this role, while, in Rhodobacter sphaeroides, the ethylmalonyl-CoA pathway is used for acetate assimilation. Using proteomic analysis, we were able to identify and quantify more than 1700 unique proteins, representing almost one-half of the theoretical proteome of the strain. Our data reveal that a pyruvate : ferredoxin oxidoreductase (NifJ) could be used for the direct assimilation of acetyl-CoA through pyruvate, potentially representing a new redox-balancing reaction. We additionally propose that the ethylmalonyl-CoA pathway could also be involved in acetate assimilation by the examined strain, since specific enzymes of this pathway were all upregulated and activity of crotonyl-CoA reductase/carboxylase was increased in acetate conditions. Surprisingly, we also observed marked upregulation of glutaryl-CoA dehydrogenase, which could be a component of a new pathway for acetate photoassimilation. Finally, our data suggest that citramalate could be an intermediate of the branched-chain amino acid biosynthesis pathway, which is activated during acetate assimilation, rather than a metabolite of the so-called citramalate cycle.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Rhodospirillum rubrum / Luz / Acetatos Idioma: En Revista: Microbiology (Reading) Asunto de la revista: MICROBIOLOGIA Año: 2015 Tipo del documento: Article País de afiliación: Bélgica Pais de publicación: Reino Unido
Texto completo
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Rhodospirillum rubrum / Luz / Acetatos Idioma: En Revista: Microbiology (Reading) Asunto de la revista: MICROBIOLOGIA Año: 2015 Tipo del documento: Article País de afiliación: Bélgica Pais de publicación: Reino Unido