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. 2015 Jan 20;108(2):315–324. doi: 10.1016/j.bpj.2014.11.3469

Figure 2.

Figure 2

Nucleotide exchange experiments. (A) Schematic illustration of the experimental setup. A prohead-motor complex is attached to one microsphere and held in one optical trap (left), and a single DNA molecule is attached by one end to a second microsphere and its other end is packaged into the prohead. (B and C) Examples of nucleotide exchange experiments. The motor is stalled by addition of γS-ATP, ATP is reintroduced, and the motor is observed to restart after a delay (restart time). (B) Example of a measurement at low filling (22% genome packaged), showing a short restart time of 5 s. (C) Example of a measurement at high filling (75%), showing a very long restart time of 110 s. (D) Mean time to restart after nucleotide exchange. The dependence of the mean restart time after exchange from γS-ATP to ATP on prohead filling (n = 304 packaging events) is shown. Error bars indicate mean ± SE.