Theory for the Acoustic Raman Modes of Proteins

TL;DR

This paper develops a theoretical framework linking acoustic Raman resonances to protein collective modes, using an elastic network model and polarizability calculations, proposing EAR as a new experimental method.

Contribution

It introduces a theoretical approach connecting EAR spectroscopy resonances with protein acoustic modes, expanding the tools for studying protein dynamics.

Findings

Theoretical spectra agree with experimental EAR data.

Elastic network model effectively predicts protein acoustic modes.

EAR spectroscopy can be used to study protein acoustic modes.

Abstract

We present a theoretical analysis that associates the resonances of extraordinary acoustic Raman (EAR) spectroscopy [Wheaton et al., Nat Photon 9, 68 (2015)] with the collective modes of proteins. The theory uses the anisotropic elastic network model to find the protein acoustic modes, and calculates Raman intensity by treating the protein as a polarizable ellipsoid. Reasonable agreement is found between EAR spectra and our theory. Protein acoustic modes have been extensively studied theoretically to assess the role they play in protein function; this result suggests EAR as a new experimental tool for studies of protein acoustic modes.