Fast Initiation of Peptide and Protein Folding Processes

The investigation of fast processes of peptide and protein folding has received increasing attention in the last years, driven by the development of new experimental approaches that make it possible to go beyond the millisecond time resolution of standard stopped-flow or rapid mixing techniques. The new methods allow the direct observation of important first steps such as hydrophobic collapse or secondary structure formation during the transition from the disordered polypeptide to the functional protein. However, most of these techniques are limited to a very narrow range of proteins or have other experimental restrictions and shortcomings. This review, after an overview and discussion of previously employed methods, describes a novel fast optical trigger for protein folding. This optical trigger has the potential to be used in the study of a wide variety of proteins and peptides without any of the restrictions of previous approaches. In an initial application of this technique, α-helix folding in short peptides was investigated.