title: The hyperthermophilic bacterium Aquifex aeolicus: from respiratory pathways to extremely resistant enzymes and biotechnological applications.
abstract: Aquifex aeolicus isolated from a shallow submarine hydrothermal system belongs to the order Aquificales which constitute an important component of the microbial communities at elevated temperatures. This hyperthermophilic chemolithoautotrophic bacterium, which utilizes molecular hydrogen, molecular oxygen, and inorganic sulfur compounds to flourish, uses the reductive TCA cycle for CO(2) fixation. In this review, the intricate energy metabolism of A. aeolicus is described. As the chemistry of sulfur is complex and multiple sulfur species can be generated, A. aeolicus possesses a multitude of different enzymes related to the energy sulfur metabolism. It contains also membrane-embedded [NiFe] hydrogenases as well as oxidases enzymes involved in hydrogen and oxygen utilization. We have focused on some of these proteins that have been extensively studied and characterized as super-resistant enzymes with outstanding properties. We discuss the potential use of hydrogenases in an attractive H(2)/O(2) biofuel cell in replacement of chemical catalysts. Using complete genomic sequence and biochemical data, we present here a global view of the energy-generating mechanisms of A. aeolicus including sulfur compounds reduction and oxidation pathways as well as hydrogen and oxygen utilization.
authors.affiliation: Unité de Bioénergétique et Ingénierie des Protéines, UMR7281-FR3479, CNRS, Aix-Marseille Université, Marseille, France. guiral@imm.cnrs.fr
authors.forename: Marianne
authors.initials: M
authors.lastname: Guiral
authors.forename: Laurence
authors.initials: L
authors.lastname: Prunetti
authors.forename: Clément
authors.initials: C
authors.lastname: Aussignargues
authors.forename: Alexandre
authors.initials: A
authors.lastname: Ciaccafava
authors.forename: Pascale
authors.initials: P
authors.lastname: Infossi
authors.forename: Marianne
authors.initials: M
authors.lastname: Ilbert
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lojou
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Giudici-Orticoni
mesh_terms: D001419:Bacteria / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001709:Biotechnology; D004734:Energy Metabolism; D006358:Hot Temperature; D006859:Hydrogen / Q000378:metabolism; D006864:Hydrogenase / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D013455:Sulfur / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D013455:Sulfur; D006859:Hydrogen; D010088:Oxidoreductases; D006864:Hydrogenase