factor of nearly 2 than for the folded state but decreases with temperature. Finally, the static contribution to the FFCF, Δs, increases almost threefold relative to the folded protein and also decreases with temperature. These trends have a straight- forward interpretation in terms of the protein dynamics. The decrease of Δs with increasing temperature reflects the fact that, as the temperature increases, more of the protein conformational fluctuations occur within the ~100 ps measurement time. This trend is consistent with the temperature dependent rise in Δ1. Thus, the unfolded state exhibits much more heterogeneity than the folded state regardless of whether the denaturation is thermal or chemical. In addition, as the temperature increases, the unfolded protein samples the available conformational space increas- ingly rapidly. Thus, these results suggest that the unfolded state represent a rugged conformational landscape with many local minima and that the increasing temper- ature increases the rate of crossing the kinetic barriers between these minima, leading to the increased rate of sampling the conformational distribution.