FIG. 2.

Endonuclease activity of His₆-YqfS against a plasmid containing AP sites. Aliquots (600 ng) of His₆-YqfS were incubated with 100 ng of either untreated (U-pB [lane 4]) or AP-containing sites (AP-pB [lane 3]) of pBluescript. Lane 1, AP sites-containing plasmid incubated with 50 mM Tris-HCl (pH 7.5)-300 mM NaCl; lane 2, untreated plasmid incubated with 50 mM Tris-HCl (pH 7.5)-300 mM NaCl. The reactions were incubated at 37°C for 30 min and then analyzed by electrophoresis on a 1% agarose gel stained with ethidium bromide.