title: Identification and characterization of 2-keto-3-deoxygluconate kinase and 2-keto-3-deoxygalactonate kinase in the haloarchaeon Haloferax volcanii.
abstract: The halophilic archaeon Haloferax volcanii has been proposed to degrade glucose via the semi-phosphorylative Entner-Doudoroff pathway, involving 2-keto-3-deoxygluconate kinase (KDGK) as key enzyme. So far, neither the enzyme has been characterized nor the encoding gene has been identified. In the genome of H. volcanii, two genes, HVO_0549 (kdgK1) and HVO_A0328 (kdgK2), are annotated encoding putative KDGK-1 and KDGK-2. To identify the physiological role of both kinases, transcriptional regulation analyses of both genes and growth experiments of the respective deletion mutants were performed on different sugars. Further, recombinant KDGK-1 and KDGK-2 were characterized. Together, the data indicate that KDGK-1 represents the functional constitutively expressed KDG kinase in glucose degradation, whereas KDGK-2 is an inducible 2-keto-3-deoxygalactonate kinase likely involved in d-galactose catabolism.
authors.affiliation: Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Kiel, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Pickl
authors.affiliation: Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Kiel, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Johnsen
authors.affiliation: Department of Chemistry, University of Bath, Bath, UK.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Archer
authors.affiliation: Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Kiel, Germany peter.schoenheit@ifam.uni-kiel.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Schönheit
mesh_terms: D000595:Amino Acid Sequence; D005690:Galactose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006019:Glycolysis; D019622:Haloferax volcanii / Q000201:enzymology* / Q000235:genetics; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D017853:Phosphotransferases (Alcohol Group Acceptor); C021471:2-keto-3-deoxygluconokinase; C032243:2-dehydro-3-deoxygalactonokinase; D005947:Glucose; D005690:Galactose
keywords: Haloarchaea; glucose degradation; semi-phosphorylative Entner–Doudoroff pathway; substrate promiscuity