Simulation Study of Chiral Two-Dimensional Ultraviolet Spectroscopy of the Protein Backbone

摘要

Abstract: Amide n π* and π π* excitations around 200 nm are prominent spectroscopic signatures ofnthe protein backbone, which are routinely used in ultraviolet (UV) circular dichroism for structurencharacterization. Recently developed ultrafast laser sources may be used to extend these studies to twondimensions. We apply a new algorithm for modeling protein electronic transitions to simulate two-dimensionalnUV photon echo signals in this regime and to identify signatures of protein backbone secondary (and tertiary)nstructure. Simulated signals for a set of globular and fibrillar proteins and their specific regions revealncharacteristic patterns of helical and sheet secondary structures. We investigate how these patterns varynand converge with the size of the structural motif. Specific chiral polarization configurations of the UV pulsesnare found to be sensitive to aspects of the protein structure. This information significantly augments thatnavailable from linear circular dichroism.