Unbiased Cold Denaturation: Low- and High-Temperature Unfolding of Yeast Frataxin under Physiological Conditions

摘要

Protein unfolding can be induced both by heating and by cooling from ambient temperatures. Accurate analysis of heat and cold denaturation processes has the potential to unveil hitherto obscure aspects of protein stability and dynamics. For instance, while heat denaturation is generally highly cooperative, cold denaturation has been suggested to occur in a non-cooperative fashion. This view has been recently supported by an NMR study of ubiquitin in reverse micelles at very low temperatures, but this is still controversial since Van Horn et al., on the basis of similar NMR data, and Kitahara et al., by an NMR study at 2 kbar, found a simple two-state behavior for the low-temperature unfolding of ubiquitin.