Computational investigation of aphid odorant receptor structure and binding function

Abstract

Odorant receptors (OR) play a critical role in signal transduction and olfactory recognition in insects. Unfortunately, insect ORs are difficult to express and purify, and limited structural data are available. Computational methods were used to predict models for aphid ORs, and binding interactions with aphid pheromones and other semiochemicals were investigated. Previously functionally characterised ORs from the pea aphid, Acyrthosiphon pisum, ApisOR4 and ApisOR5, were screened against functional ligands. ApisOR5 had a defined binding site, and had predicted interactions with the aphid alarm pheromone, (E)-β-farnesene. ApisOR4 had multiple distinct binding sites and showed broad tuning to multiple odorants. Screening of six other highly conserved ORs showed some interactions and potential enantiomeric discrimination between the aphid sex pheromone components (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol. These results indicate that specific binding sites may be more critical to understanding olfactory activity of ligands and ORs than kinetic data, and greater knowledge of the method of action of ORs is required.

Communicated by Ramaswamy H. Sarma

Keywords:

• Odorant receptor
• computational
• aphid
• alphafold
• molecular dynamics

Acknowledgements

CS was supported by a Biotechnology and Biological Sciences Research Council (BBSRC) Doctoral Training Partnership studentship (reference 1804053) awarded to Rothamsted Research and the University of Nottingham.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work at Rothamsted Research formed part of the Smart Crop Protection (SCP) strategic programme (BBS/OS/CP/000001) funded through Biotechnology and Biological Sciences Research Council’s Industrial Strategy Challenge Fund.