Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Transmembrane segment 3 of Drosophila melanogaster odorant receptor subunit 85b contributes to ligand-receptor interactions.
Nichols AS, Luetje CW.
???displayArticle.abstract???
The OR class insect odorant receptors are ligand-gated ion channels comprised of at least one common subunit (OR83b in Drosophila) and at least one putative odorant-binding subunit. However, little else is known about the molecular details of insect OR architecture. For example, nothing is known about how these receptors bind odorants, greatly limiting efforts to develop insect OR-targeted compounds for the control of insects involved in disease propagation and agricultural damage. Here we identify a portion of a Drosophila OR that is involved in odorant activation of the receptor. Using the substituted cysteine accessibility method, we identified residues 146-150 of OR85b, located at the predicted interface between transmembrane segment 3 (TMS3) and extracellular loop 2 (ECL2), as playing a role in odorant (2-heptanone) activation. We found that occupation of the receptor by the competitive antagonist 2-nonanone protected the receptor from methanethiosulfonate action at position 148, placing this region close to the odorant-binding site. In addition, mutations at positions 142 and 143 within TMS3 altered odorant sensitivity. Our results identify the involvement of the extracellular half of TMS3 in Drosophila OR85b in odorant activation of the receptor. This finding can serve as a starting point for future detailed analysis of the molecular basis for odorant recognition by insect ORs, a novel class of ligand-gated channel.
Benton,
Variant ionotropic glutamate receptors as chemosensory receptors in Drosophila.
2009, Pubmed
Benton,
Variant ionotropic glutamate receptors as chemosensory receptors in Drosophila.
2009,
Pubmed Benton,
Atypical membrane topology and heteromeric function of Drosophila odorant receptors in vivo.
2006,
Pubmed Hallem,
Insect odor and taste receptors.
2006,
Pubmed Hallem,
Coding of odors by a receptor repertoire.
2006,
Pubmed Hallem,
The molecular basis of odor coding in the Drosophila antenna.
2004,
Pubmed Hallem,
The odor coding system of Drosophila.
2004,
Pubmed Jones,
Functional conservation of an insect odorant receptor gene across 250 million years of evolution.
2005,
Pubmed Jones,
A model recognition approach to the prediction of all-helical membrane protein structure and topology.
1994,
Pubmed Käll,
An HMM posterior decoder for sequence feature prediction that includes homology information.
2005,
Pubmed Karlin,
Substituted-cysteine accessibility method.
1998,
Pubmed Krogh,
Predicting transmembrane protein topology with a hidden Markov model: application to complete genomes.
2001,
Pubmed Larsson,
Or83b encodes a broadly expressed odorant receptor essential for Drosophila olfaction.
2004,
Pubmed Liman,
Subunit stoichiometry of a mammalian K+ channel determined by construction of multimeric cDNAs.
1992,
Pubmed
,
Xenbase Lu,
Odor coding in the maxillary palp of the malaria vector mosquito Anopheles gambiae.
2007,
Pubmed Lundin,
Membrane topology of the Drosophila OR83b odorant receptor.
2007,
Pubmed Nakagawa,
Controversy and consensus: noncanonical signaling mechanisms in the insect olfactory system.
2009,
Pubmed Neuhaus,
Odorant receptor heterodimerization in the olfactory system of Drosophila melanogaster.
2005,
Pubmed Pitts,
A highly conserved candidate chemoreceptor expressed in both olfactory and gustatory tissues in the malaria vector Anopheles gambiae.
2004,
Pubmed Smart,
Drosophila odorant receptors are novel seven transmembrane domain proteins that can signal independently of heterotrimeric G proteins.
2008,
Pubmed Spyropoulos,
TMRPres2D: high quality visual representation of transmembrane protein models.
2004,
Pubmed Touhara,
Sensing odorants and pheromones with chemosensory receptors.
2009,
Pubmed Vosshall,
A spatial map of olfactory receptor expression in the Drosophila antenna.
1999,
Pubmed Wanner,
A honey bee odorant receptor for the queen substance 9-oxo-2-decenoic acid.
2007,
Pubmed
,
Xenbase Wetzel,
Functional expression and characterization of a Drosophila odorant receptor in a heterologous cell system.
2001,
Pubmed
,
Xenbase Wicher,
Drosophila odorant receptors are both ligand-gated and cyclic-nucleotide-activated cation channels.
2008,
Pubmed Wistrand,
A general model of G protein-coupled receptor sequences and its application to detect remote homologs.
2006,
Pubmed
