Structural insights in the folding of small single-domain proteins

Understanding the mechanism by which a polypeptide chain folds into its unique native structure requires a complete and detailed description of the structural and dynamic properties of all the species populated in the folding process. In the case of small single domain proteins, experimental studies are defining the structures of denatured states, folding intermediates and transition states at nearly atomic resolution. Further, the synergy between theoreticians and experimentalists is now allowing the detailed description of whole (un)folding pathways. Here, we discuss some of the general structural aspects of the denatured states, folding intermediates and transition states that are beginning to emerge from these studies.