Fig. 8.

Electrochemistry of the NER helicase XPD on a substrate containing a 9-mer 5’ single-stranded overhang. On this substrate, electro-chemical experiments with XPD yielded a signal similar in potential and general form to those from BER proteins (left, blue CV at right). The addition of ATP, known to stimulate helicase activity in XPD, resulted in a substantial increase in current as a result of enhanced electronic coupling between the [4Fe4S] cluster and the DNA base stack (middle, red CV at right). All images in this figure were adapted from Mui, T. P., Fuss, J. O., Ishida, J. P., Tainer, J. A., & Barton, J. K. (2011) ATP-stimulated, DNA-mediated redox signaling by XPD, a DNA repair and transcription helicase. Journal of the American Chemical Society, 133, 16378–16381.