Figure EV3. RPA specifically stimulates XPF‐ERCC1 activity on the strand with a 3′‐ssDNA arm of a fork structure and its stimulation requires a minimum of 23 nucleotides ssDNA arms.

1. The nuclease activity of XE in the presence and absence of RPA on fork substrates 3′[³²P]‐radiolabelled either on the “top” or the “bottom” strand. XPF‐ERCC1 activity is not detectable on the bottom strand of the fork substrates, which have a 5′‐ssDNA arm.
2. The nuclease activity of XE in the presence and absence of RPA on simple fork substrates containing arms of 23, 13 or 3 nucleotides.

Source data are available online for this figure.