title: Gentisate 1,2-dioxygenase from Haloferax sp. D1227.
abstract: Gentisate 1,2-dioxygenase from the extreme halophile Haloferax sp. D1227 (Hf. D1227) was purified using a three-step procedure. The enzyme was found to be a homotetramer of 42,000 +/- 1,000 Da subunits, with a native molecular weight of 174,000 +/- 6,000 Da. The optimal salt concentration, temperature, and pH for enzyme activity were 2 M KCl or NaCl, 45 degrees C, and pH 7.2, respectively. The gene encoding Hf. D1227 gentisate 1,2-dioxygenase was cloned, sequenced, and expressed in Haloferax volcanii. The deduced amino acid sequence exhibited a 9.2% excess acidic over basic amino acids typical of halophilic enzymes. Four novel histidine clusters and a possible extradiol dioxygenase fingerprint region were identified.
authors.affiliation: Department of Microbiology, Michigan State University, East Lansing 48824-1101, USA.
authors.forename: W
authors.initials: W
authors.lastname: Fu
authors.forename: P
authors.initials: P
authors.lastname: Oriel
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002384:Catalysis; D003001:Cloning, Molecular; D019641:DNA, Archaeal; D049308:Dioxygenases; D004795:Enzyme Stability; D019622:Haloferax volcanii / Q000201:enzymology* / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010105:Oxygenases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012492:Salts; D013696:Temperature
chemical_list: D019641:DNA, Archaeal; D012492:Salts; D010105:Oxygenases; D049308:Dioxygenases; C026247:gentisate 1,2-dioxygenase