Exploring the Protein Folding Dynamics of Beta3s with Two‐Dimensional Ultraviolet (2DUV) Spectroscopy

Abstract

Ultraviolet (UV) spectra of proteins originate from electronic excitations of their backbone chromophore and aromatic side chains and provide a sensitive probe of the secondary structure. Recently developed femtosecond lasers allow multidimensional spectroscopy to be extended into the UV regime. Two‐dimensional UV (2DUV) techniques, with short pulses, provide a promising tool to study the structures and dynamics of proteins. We combined 2DUV spectroscopy and molecular dynamics generated free energy profiles to simulate the protein electronic transitions and UV photon echo signals to monitor the protein folding process of the small protein Beta3s. Near‐ultraviolet (NUV) and far‐ultraviolet (FUV) signals illustrate the variation of the 2D correlation plots when the protein evolves along the underlying free energy landscape. Chiral polarization configurations of the NUV and FUV pulses are sensitive to protein structural evolution. This work provides a protocol for applying multidimensional UV spectroscopy to study protein folding.

Near-Ultraviolet Circular Dichroism and Two-Dimensional Spectroscopy of Polypeptides

“…The interpretation of complex and often congested spectra benefits considerably from computational modelling. Several theoretical studies have predicted the two-dimensional spectra of proteins in the far-ultraviolet [ 8 , 9 , 10 ] and in the near-ultraviolet [ 11 , 12 , 13 ], for example, characterising the signals expected for amyloid fibrils. Conti et al [ 14 ] have recently provided a comprehensive overview of the state-of-the-art theoretical methods and their application to ultrafast spectroscopy.…”