Characterization of a thermostable archaeal polynucleotide kinase homologous to human Clp1

PhoClp1 is thermophilic. Reaction mixtures (10 μL) containing 50 mM Tris-HCl at pH 7.5, (DNA kinase) or 50 mM Tris-acetate at pH 6.5, (RNA kinase), 10 mM MgCl₂, 500 μM [γ³²P]ATP, 5 μM 24-mer 5′-OH DNA or 5′-OH RNA as shown, and 0.3 pmol PhoClp1 were incubated for 15 min at the specified temperature. The reactions were initiated by adding PhoClp1 to preheated reaction mixtures. The extents of product formation are plotted as a function of reaction temperature.