Fig. 4.

Conformational dynamics of MangoIV. a A schematic of MangoIV under tension. In view of the proposed structural similarity, the representation is constructed with reference to MangoI crystal structure^{9, 18}. The Cy5 and Cy3 dyes adjacent to C₄₀ and G₁ are shown as red and green asterisks, respectively. To mimic the intracellular ionic conditions, all data shown in this figure were collected in a buffer containing 100 mM K⁺ and 1 mM Mg²⁺. b E histograms of MangoIV, in the absence of force. c A representative FRET time trajectory of a single molecule of MangoIV over two pulling cycles. d Average E vs force response. e Distributions of unfolding (top) and refolding forces (bottom). (N = 51 for both). f A schematic of TO1-MangoIV module under tension. Force (F) applied on the construct is shown by arrows. g E histogram of MangoIV in a buffer containing saturated concentrations of TO1, in the absence of force. h A representative smFRET time trajectory of MangoIV in the presence of TO1. The orange arrow indicates photobleaching of the dyes. i Average E vs force response in TO1 containing buffer. j Distributions of unfolding and refolding forces. (N = 36 for both). The time trajectories were acquired at an integration time of 20 ms. The red curves in e and j represent force distributions estimated from the Dudko–Szabo models^{46, 47}. All error bars represent standard errors