Figure 4.

Osmolytes specifically affect the first step in folding. (a) Representative refolding trace (force-clamp at 5 pN) fit to the Bayesian HMM. The graph shows the extension data with states assigned according to the Bayesian HMM: the unfolded state is shown in blue, the intermediate in green, and the native in red. The width of the shaded bars under the data represents the mean ± 1 SD, which in this case is: μ_U ± σ_U = 25.3 ± 2.0 nm, μ_I ± σ_I = 10.9 ± 3.8 nm, and μ_N ± σ_N = 0.0 ± 1.4 nm. On the right is the probability distribution of the states in this refolding transition. (b) Fits of each rate in the folding transition as determined by the BHMM for buffer (black), sorbitol (red), and TMAO (orange). The rates showing significant change are the k_I-U and k_U-I rates denoted by ^∗p < 0.05. To see this figure in color, go online.