Figure 9.

(A) Distribution of the translocation times for the events identified as hairpin translocations in the forward and backward cases. Note that the most probable translocation time is five times slower in the backward geometry (50 ms 8 ± 5 ms) than in the forward geometry (10 ms ± 5 ms). The distribution in the backward direction spans also a decade more toward large unzipping times. We attribute these differences to different modes of force application on the unzipping fork and to enhanced thermal fluctuations of the unzipping force in the backward direction. (B) Schematic representation of the two possible opening modes: shear and traction.