ABSTRACT
Fundamental questions of how a protein or peptide folds to its native state have been probed using multiple spectroscopic techniques and multiple protein/peptide systems. As a result there has been progress toward a better understanding of folding concepts such as polypeptide collapse, the dynamics of the unfolded and the partly unfolded states, folding heterogeneity, classical versus energy landscape folding mechanisms, and on-pathway versus off-pathway intermediates. These advances were achievable in part because of technological improvements that allowed for fast detection and fast initiation of protein-folding/unfolding reactions. Thus it became possible to capture the earliest dynamics of protein folding that occurred during the burst phase of conventional stopped-flow instruments.
