Movie S2.

Unwinding of a λ DNA molecule in a solution containing 100 nM RecQ and AF488SSB. Initially, the DNA is not seen due to the absence of fluorescent dye. The flow, when on, is from left to right, and the RecQ and AF488SSB fill the channel 24 s into the movie. The elapsed time is indicated in hours:minutes:seconds. (Scale bar, 5 μm.)