Characterization of a thermophilic DNA ligase from the archaeon Thermococcus fumicolans

A PCR protocol was used to identify and sequence a gene encoding a DNA ligase from Thermococcus fumicolans (Tfu). The recombinant enzyme, expressed in Escherichia coli BL21(DE3) pLysS, was purified to homogeneity and characterized. The optimum temperature and pH of Tfu DNA ligase were 65 °C and 7.0, respectively. The optimum concentration of MgCl2, which is indispensable for the enzyme activity, was 2 mM. We showed that Tfu DNA ligase displayed...