Primary Peptide Folding Dynamics Observed with Ultrafast Temperature Jump

The timescale of alpha-helix initiation was measured with ultrafast time-resolved fluorescence spectroscopy following laser temperature jump. The observed timescales were corroborated, and the atomistic mechanism elucidated, via ensemble-convergent all-atom molecular dynamics. The initiation of the first helical turn from the random coil occurs in a few nanoseconds and represents the fastest possible transition from unstructured to partially structured peptides and proteins.