Two-dimensional vibrational optical probes for peptide fast folding investigation.

A simulation study shows that early protein folding events may be investigated by using a recently developed family of nonlinear infrared techniques that combine the high temporal and spatial resolution of multidimensional spectroscopy with the chirality-specific sensitivity of amide vibrations to structure. We demonstrate how the structural sensitivity of cross-peaks in two-dimensional correlation plots of chiral signals of an alpha helix and a beta hairpin may be used to clearly resolve structural and dynamical details undetectable by one-dimensional techniques (e.g. circular dichroism) and identify structures indistinguishable by NMR.