Fig. 4.

Transport barriers and kinetic parameters. a Effective free energy barriers ΔF corresponding to different regions of the J_BB flux profile. Region A has nearly no barrier, but as the gradient becomes large, a barrier starts to form and increases in region B. In C, this barrier decreases until in D it is zero to within statistical error (albeit, the uncertainty is large in this last region due to the limited number of samples for large temperature gradients, which occur only at short times). b Backbone rate distributions (k_BB) for helical Aib₁₀ conformers. Rate constants are parameterized by the temperature gradient Δ_ijT_eff between adjacent residues and c partitioned into low-temperature (blue; 230–270 K) and high-temperature (red; 290–330 K) regimes. The error bars are plus/minus one standard error