FIGURE 5.

Stiffness of poly(U) mRNA and 16S rRNA tethers. (a) Representative autocorrelation plots of the x-position shown with single exponential fits to extract time constants from a microsphere tethered by a single 1.9–2.6 kb poly(U) mRNA, at 0 mM and 10 mM Mg²⁺, as indicated. (b) Energy profiles for a representative 16S rRNA-tethered bead in 0 mM and 10 mM Mg²⁺, as indicated. (c,d) Adjusted time constants obtained from the autocorrelation function of the moving-averaged x-position and plotted as a function of x-,y-rms motion for 1.4–1.9 kb poly(U) mRNA (c) and 16S rRNA (d). Data in panels c and d are reasonably well represented by linear regression fits, as shown.