Figure 2.

Establishing a stiff linker system. A) Experimental setup. B) Force-extension data obtained with six, eight, ten, and twelve-helix bundles. Apparent linear extensibility (k_app) upon stretching the bundles beyond their contour lengths (arrows). C) Graph of k_app when varying the laser trap stiffness. Inset: force-extension response of an eight-helix-bundle linker at different values of trap stiffness. Darker shade indicates greater trap stiffness. D) Force-dependent noise amplitudes when using ten-helix bundles (cyan/blue) versus conventional dsDNA linkers (orange/brown). Dashed lines: theoretically predicted noise suppression (see Figure 1 C). Experiments were also carried out using double linkers that flank a short dsDNA bridging element (green circles).