title: [NiFe] hydrogenases from the hyperthermophilic bacterium Aquifex aeolicus: properties, function, and phylogenetics.
abstract: Genes potentially coding for three distinct [NiFe] hydrogenases are present in the genome of Aquifex aeolicus. We have demonstrated that all three hydrogenases are expressed under standard growth conditions of the organism. Two hydrogenases were further purified to homogeneity. A periplasmically oriented hydrogenase was obtained in two forms, i.e., as a soluble enzyme containing only the two essential subunits and as a detergent-solubilized complex additionally containing a membrane-integral b-type cytochrome. The second hydrogenase purified was identified as a soluble cytoplasmic enzyme. The isolated enzymes were characterized with respect to biochemical/biophysical parameters, activity, thermostability, and substrate specificity. The phylogenetic positioning of all three hydrogenases was analyzed. A model for the metabolic roles of the three enzymes is proposed on the basis of the obtained results.
authors.affiliation: Bioénergétique et Ingénierie des Protéines, CNRS, IBSM, 31 chemin Joseph Aiguier, 13402, Marseille Cedex 20, France.
authors.forename: Marianne
authors.initials: M
authors.lastname: Brugna-Guiral
authors.forename: Pascale
authors.initials: P
authors.lastname: Tron
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Nitschke
authors.forename: Karl-Otto
authors.initials: KO
authors.lastname: Stetter
authors.forename: Benedicte
authors.initials: B
authors.lastname: Burlat
authors.forename: Bruno
authors.initials: B
authors.lastname: Guigliarelli
authors.forename: Mireille
authors.initials: M
authors.lastname: Bruschi
authors.forename: Marie Thérèse
authors.initials: MT
authors.lastname: Giudici-Orticoni
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D045303:Cytochromes b / Q000235:genetics; D004578:Electron Spin Resonance Spectroscopy; D004795:Enzyme Stability; D005798:Genes, Bacterial; D006864:Hydrogenase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009876:Operon; D010802:Phylogeny; D021122:Protein Subunits; D040901:Proteomics; D017386:Sequence Homology, Amino Acid; D012995:Solubility; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D007527:Isoenzymes; D021122:Protein Subunits; D045303:Cytochromes b; C043296:nickel-iron hydrogenase; D006864:Hydrogenase