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. Author manuscript; available in PMC: 2018 Jul 13.
Published in final edited form as: Methods Enzymol. 2016 Dec 7;582:387–414. doi: 10.1016/bs.mie.2016.09.038

Figure 5. Sub-nucleotide steps in helicase movement.

Figure 5

a) Levels observed when stepping the indicated DNA strand through MspA with phi29 DNAP controlling the DNA motion and b) with helicase T. gammatolerans Hel308 controlling the DNA motion. The observed current patterns are similar; however the helicase takes twice as many steps. c) Comparison of the half-lives of each level at two different concentrations of ATP. d) Ratio of observed half-lives from c). Interestingly, the duration of odd-numbered levels (orange diamonds) varies as [ATP] changes, while even-numbered levels (blue diamonds) remain unchanged. With the ability to resolve such small substates and observe their chemical dependencies, SPRNT has the potential to shed light on how such motors actually do their work. Modified from (Derrington et al., 2015).