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. 2019 May 8;14(5):e0215696. doi: 10.1371/journal.pone.0215696

Fig 5. Synergistic effects of SN38 and HMGA2 on supercoil relaxation by human topoisomerase I.

Fig 5

(A-B) In the presence of 5 nM TOP1 and 5 μM SN38, fast relaxation of (-) scDNA and slow relaxation of (+) scDNA are observed indicated by segmented extension increases linearly. The scatter plot of the raw data is fitted by piecewise linear regression (also see S4 Fig). (C-D) In the presence of 5 nM TOP1 and 500 nM HMGA2, both (-) scDNA and (+) scDNA are relaxed in a jump-pause manner for a similar duration. (E-F) In the presence of 5 nM TOP1, 5 μM SN38 and 500 nM HMGA2, many of the relaxation events are greatly impeded. The mixed features of extension increase (linear and pause-jump) can be observed. (G) Box plot of relaxation time (grey circle) summarized from (A-F). The mean is shown by the red line, grey and dark grey areas represent the distribution of SD and SEM. p-value is calculated by Wilcoxon rank-sum test. A different scale of the same plot is shown in S4 Fig. in order to highlight the different relaxation times due to the sole presence of either SN38 or HMGA2.