– We long ago performed the experiments that ask whether RPA or SSB might stimulate CMG unwinding prior to submitting the original manuscript, and have now included this data as a Figure 2—figure supplement 2. We should note that SSB/RPA can’t be added to reactions before CMG as it prevents CMG loading (as we published earlier). Thus, we let the CMG helicase reaction proceed for 10 min, and then add either Mcm10, RPA or SSB. The result shows that Mcm10 provides strong stimulation of the CMG helicase while neither RPA nor SSB affect CMG activity.