초고온성 고세균 써모코커스로부터 haloacid dehalogenase

Abstract

As a part of genomic research of the Thermococcus onnurineus NA1, a hyperthermophilic archaeon collected from a deep-sea hydrothermal vent area, a gene annotated as a hydrolase of the haloacid dehalogenase superfamily was investigated to assign its function. The gene was cloned and expressed in Escherichia coli and its recombinant protein was purified by Co2+-IMAC-Sepharose column chromatography. The enzyme possessed phosphatase activity, which wasstrictly dependent on the presence of divalent metal ion such as Co2+, Ni2+, Mn2+, or Mg2+ at optimum pH 6.5. The enzyme showed broad substrate specificity toward phosphorylated substrates (sugars, nucleotides, pyrophosphate and amino acids). While phosphatases of HAD superfamily exhibited nucleotidase activities, this phosphatase revealed high catalytic efficiency and affinity toward canonical 5¢-nucloside tri- and diphosphatates as well as nucleotidase activity.