title: A novel octameric AMP-forming acetyl-CoA synthetase from the hyperthermophilic crenarchaeon Pyrobaculum aerophilum.
abstract: AMP-forming acetyl-CoA synthetases (ACSs) are ubiquitous in all three domains of life. Here, we report the first characterization of an ACS from a hyperthermophilic organism, from the archaeon Pyrobaculum aerophilum. The recombinant ACS, the gene product of ORF PAE2867, showed extremely high thermostability and thermoactivity at temperatures around 100 degrees C. In contrast to known monomeric or homodimeric mesophilic ACSs, the P. aerophilum ACS was a 610 kDa homooctameric protein, with a significant lower content of thermolabile (Cys, Asn, and Gln) and higher content of charged (Glu, Lys, and Arg) amino acids. Kinetic analyses revealed an unusual broad substrate spectrum for organic acids and an extremely high affinity for acetate (K(m) 3 microM).
authors.affiliation: Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Am Botanischen Garten 1-9, D-24118 Kiel, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Bräsen
authors.forename: Claus
authors.initials: C
authors.lastname: Urbanke
authors.forename: Peter
authors.initials: P
authors.lastname: Schönheit
mesh_terms: D000106:Acetate-CoA Ligase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000249:Adenosine Monophosphate / Q000096:biosynthesis*; D000595:Amino Acid Sequence; D002384:Catalysis; D004795:Enzyme Stability; D008969:Molecular Sequence Data; D041543:Pyrobaculum / Q000201:enzymology*; D016415:Sequence Alignment; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D000249:Adenosine Monophosphate; D000106:Acetate-CoA Ligase