How Far Does a Receptor Influence Vibrational Properties of an Odorant?

PLoS One. 2016 Mar 25;11(3):e0152345. doi: 10.1371/journal.pone.0152345. eCollection 2016.

Abstract

The biophysical mechanism of the sense of smell, or olfaction, is still highly debated. The mainstream explanation argues for a shape-based recognition of odorant molecules by olfactory receptors, while recent investigations suggest the primary olfactory event to be triggered by a vibrationally-assisted electron transfer reaction. We consider this controversy by studying the influence of a receptor on the vibrational properties of an odorant in atomistic details as the coupling between electronic degrees of freedom of the receptor and the vibrations of the odorant is the key parameter of the vibrationally-assisted electron transfer. Through molecular dynamics simulations we elucidate the binding specificity of a receptor towards acetophenone odorant. The vibrational properties of acetophenone inside the receptor are then studied by the polarizable embedding density functional theory approach, allowing to quantify protein-odorant interactions. Finally, we judge whether the effects of the protein provide any indications towards the existing theories of olfaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetophenones / chemistry
  • Computer Simulation
  • Crystallography, X-Ray
  • Cysteine / chemistry
  • Electrons
  • Humans
  • Molecular Conformation
  • Molecular Dynamics Simulation
  • Odorants*
  • Olfactory Receptor Neurons / metabolism*
  • Opsins / chemistry
  • Pentanols / chemistry
  • Receptors, Odorant / metabolism
  • Smell / physiology*
  • Spectrophotometry, Infrared
  • Tyrosine / chemistry
  • Vibration*

Substances

  • Acetophenones
  • Opsins
  • Pentanols
  • Receptors, Odorant
  • Tyrosine
  • Cysteine
  • acetophenone

Grant support

The authors acknowledge supercomputer time on Stampede provided by the Texas Advanced Computing Center (TACC) at the University of Texas at Austin through Extreme Science and Engineering Discovery Environment (XSEDE) Grant XSEDE MCB-120160. The authors also thank DeIC for providing computational resources. I. A. S. is grateful for the financial support from Lundbeck Foundation, and the Russian Scientific Foundation (grant no 14-12-00342). N. H. L. and J. K. acknowledge the Lundbeck Foundation and the Danish Councils for Independent Research for financial support. J. K. thanks the Villum foundation for financial support.