FIGURE 1.

Aq793 helicase activity. DNA unwinding activity was assayed with serial dilutions of Aq793. The 20-μl unwinding reactions were incubated at 55 °C and contained 0.02 nm dsDNA substrate. The reactions were quenched after 20 min using stop solution and applied to a 20% TBE acrylamide gel as described under “Materials and Methods.” A, representative autoradiograms of TBE acrylamide gels. The DNA substrate is indicated to the left of the gel picture, and the expected mobility of dsDNA and ssDNA is shown to the right. The negative control (−) was performed using 0.02 nm of substrate incubated at 55 °C with 400 nm of Aq793 without ATP, and the positive control (+) was performed at 95 °C in the absence of Aq793. B, graph of data from TBE gel bands that were quantified using ImageQuant TL software. 3′-dT40 (solid squares), 5′-dT40 (open circles), dT40⁻ (open triangles), and the nicked substrate (solid diamonds) are represented. The points represent the averages of three separate experiments. The error bars represent the standard deviation at each point.