Olfactory receptor 1A1 is a protein that in humans is encoded by the OR1A1 gene. Olfactory receptors interact with odorant molecules in the nose, to initiate a neuronal response that triggers the perception of a smell. The olfactory receptor proteins are members of a large family of G-protein-coupled receptors (GPCR) arising from single coding-exon genes. Olfactory receptors share a 7-transmembrane domain structure with many neurotransmitter and hormone receptors and are responsible for the recognition and G protein-mediated transduction of odorant signals. The olfactory receptor gene family is the largest in the genome. The nomenclature assigned to the olfactory receptor genes and proteins for this organism is independent of other organisms. Ligands OR1A1 is relatively broadly tuned, meaning it responds to a relatively wide variety of different odor molecules. Examples of known ligands, most of which have citrus or fruity smells: (S)-(−)-citronellal Helional Heptanal Octanal Nonanal (weaker than heptanal/octanal) Hydroxycitronellal Citral Citronellol (both enantiomers, weaker than citronellal) Dihydrojasmone Thiols See also Olfactory receptor References Further reading External links Olfactory receptors