Exploring the cupin-type metal-coordinating signature of acetylacetone dioxygenase Dke1 with site-directed mutagenesis: catalytic reaction profile and Fe2+ binding stability of Glu-69->Gln mutant. (Articolo in rivista)

Type
Label
  • Exploring the cupin-type metal-coordinating signature of acetylacetone dioxygenase Dke1 with site-directed mutagenesis: catalytic reaction profile and Fe2+ binding stability of Glu-69->Gln mutant. (Articolo in rivista) (literal)
Anno
  • 2006-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1016/j.molcatb.2006.01.019 (literal)
Alternative label
  • Straganz G.D., Egger S., Aquino G., D'Auria S., Nidetzky B. (2006)
    Exploring the cupin-type metal-coordinating signature of acetylacetone dioxygenase Dke1 with site-directed mutagenesis: catalytic reaction profile and Fe2+ binding stability of Glu-69->Gln mutant.
    in Journal of molecular catalysis. B, Enzymatic (Print)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Straganz G.D., Egger S., Aquino G., D'Auria S., Nidetzky B. (literal)
Pagina inizio
  • 171 (literal)
Pagina fine
  • 178 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 39 (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Graz, Austria Istituto di Biochimica delle Proteine,CNR. (literal)
Titolo
  • Exploring the cupin-type metal-coordinating signature of acetylacetone dioxygenase Dke1 with site-directed mutagenesis: catalytic reaction profile and Fe2+ binding stability of Glu-69->Gln mutant. (literal)
Abstract
  • Glu-69 belongs to a proposed active-site consensus motif His62-X-His64-X4-Glu69 (where X is any amino acid) that acetylacetone dioxygenase Dke1 from Acinetobacter johnsonii shares with structurally related non-heme metal enzymes of the cupin protein superfamily.We report functional consequences of the site-directed replacement Glu-69¨Gln based on a detailed biochemical and kinetic characterization of the purified Dke1 mutant. Perturbations of the free energy profile of the wild-type caused by the mutation were surprisingly small, with key points of the reaction pathway such as _-diketone substrate binding, the rate-limiting reduction of dioxygen, and C C bond cleavage essentially left unaltered. Release of Fe2+ from the mutant active site occurred at twice the wild-type rate, and the thermal stability of _-sheet secondary structure in Fe2+-depleted apo-proteins was lower in the mutant. The substitution Glu-69¨Gln is thus remarkably silent regarding Dke1 function. These results do not support a unified catalytic or metal-coordinating role of Glu-69 (and its positional homologues) in O2-dependent cupin-fold enzymes. (literal)
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