FIG 4.

Binding and cleavage specificities of PfuEndoQ. (A to C) Cleavage activity toward U-, 5hU-, and Hx-containing DNA. Damaged bases were paired with either A, G, T, or C in dsDNA or remained unpaired (−, ssDNA). DNA substrates (5 nM) were incubated with PfuEndoQ (U, 50 pM [A]; 5hU, 1 nM [B]; Hx, 50 pM [C]) at 60°C for 10 min. DNA products were separated by 8 M urea-12% PAGE, and ³²P-labeled DNA strands were detected by autoradiography. (D to F) Binding activity toward U-containing (D), 5hU-containing (E), and Hx-containing (F) DNA. DNA substrates were incubated with or without PfuEndoQ (0 [−], 5, or 20 nM) at 40°C for 5 min. The products were separated by 4% PAGE, and ³²P-labeled DNA strands were detected by autoradiography. Bars, mean ± SEM for n = 3 with the individual data (dots).