Experimental mapping of short-wavelength phonons in proteins

Utsab R Shrestha; Eugene Mamontov; Hugh M O'Neill; Qiu Zhang; Alexander I Kolesnikov; Xiangqiang Chu

doi:10.1016/j.xinn.2021.100199

Experimental mapping of short-wavelength phonons in proteins

Innovation (Camb). 2021 Dec 17;3(1):100199. doi: 10.1016/j.xinn.2021.100199. eCollection 2022 Jan 25.

Authors

Utsab R Shrestha¹, Eugene Mamontov², Hugh M O'Neill², Qiu Zhang², Alexander I Kolesnikov², Xiangqiang Chu³

Affiliations

¹ UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
² Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
³ Department of Nuclear Science and Technology, Graduate School of China Academy of Engineering Physics, Beijing 100193, China.

Abstract

Phonons are quasi-particles, observed as lattice vibrations in periodic materials, that often dampen in the presence of structural perturbations. Nevertheless, phonon-like collective excitations exist in highly complex systems, such as proteins, although the origin of such collective motions has remained elusive. Here we present a picture of temperature and hydration dependence of collective excitations in green fluorescent protein (GFP) obtained by inelastic neutron scattering. Our results provide evidence that such excitations can be used as a measure of flexibility/softness and are possibly associated with the protein's activity. Moreover, we show that the hydration water in GFP interferes with the phonon propagation pathway, enhancing the structural rigidity and stability of GFP.

Keywords: collective excitations; inelastic neutron scattering; protein activity; protein dynamics.