15N NMR spin relaxation dispersion study of the molecular crowding effects on protein folding under native conditions.

The effects of macromolecular crowding on protein stability and folding kinetics have been studied using the recently developed 15N spin relaxation dispersion technique. By applying this method to a redesigned apocytochrome b562, the kinetics and thermodynamics of the protein folding processes in both the presence and the absence of crowding agents have been characterized. The result indicates that, even under the mild crowded environments (in the presence of 85 mg/mL of PEG 20K), the folding rate of the protein can speed up significantly while the unfolded rate remains unchanged within experimental error.