ABSTRACT
In this chapter, we describe the rates and routes of protein folding and unfolding. By routes, we mean the time-course of conformational changes that occur as a protein folds. At what stage during the course of the folding process does a protein acquire its secondary structures, its hydrogen bonds, its hydrophobic core, and its tight side-chain packing? Is there a general mechanism that explains commonalities of folding and unfolding routes over different sequences and folds, and as a function of external variables, such as temperature and denaturants? How can a protein “find” its native structure spontaneously and quickly from its unfolded state, sometimes within microseconds? What is the speed limit of folding, and what is the physical basis for it?
