Structural basis of odor sensing by insect heteromeric odorant receptors

Most insects, including human-targeting mosquitoes, detect odors through odorant-activated ion channel complexes consisting of a divergent odorant-binding subunit (OR) and a conserved co-receptor subunit (Orco). As a basis for understanding how odorants activate these heteromeric receptors, we report here cryo–electron microscopy structures of two different heteromeric odorant receptor complexes containing ORs from disease-vector mosquitos Aedes aegypti or Anopheles gambiae . These structures reveal an unexpected stoichiometry of one OR to three Orco subunits. Comparison of structures in odorant-bound and unbound states indicates that odorant binding to the sole OR subunit is sufficient to open the channel…

• HH
  Howard Hughes Medical Institute
• PC
  Pew Charitable Trusts
• RA
  Richard and Susan Smith Family Foundation
• KE
  Kwanjeong Educational Foundation
• NI
  National Institutes of Health