[NiFe] hydrogenases from the hyperthermophilic bacterium Aquifex aeolicus: properties, function, and phylogenetics.
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.
Brugna-Guiral
Marianne
M
Bioénergétique et Ingénierie des Protéines, CNRS, IBSM, 31 chemin Joseph Aiguier, 13402, Marseille Cedex 20, France.
Tron
Pascale
P
Nitschke
Wolfgang
W
Stetter
Karl-Otto
KO
Burlat
Benedicte
B
Guigliarelli
Bruno
B
Bruschi
Mireille
M
Giudici-Orticoni
Marie Thérèse
MT
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
D007527:Isoenzymes; D021122:Protein Subunits; D045303:Cytochromes b; C043296:nickel-iron hydrogenase; D006864:Hydrogenase