This is a dock result of allyl phenylacetate in a predicted active conformation of OR1A1. The active model was generated by applying internal contact changes similar to those known for OR51E2, mTAAR9, and non-olfactory GPCRs. This dock shows the aromatic ring of the ligand in a pi stacking position between two of the receptor’s aromatic […]
Read MoreThe function of the HXXCD/E motif in extracellular loop 2 of many ORs has been debated. One study found that this sequence makes for a strong zinc-coordinating locus, which folds into an alpha helix as it binds the Zn2+ ion. Reasonably, that study postulated that the motif may bind zinc to the extracellular end of […]
Read MoreOR51E2 is a receptor for propionic and acetic acids, and its agonists tend to smell vinegar-like. Other short chain fatty acids (SCFAs) with chains of up to 5 carbon atoms activate this protein progressively less strongly with increasing chain length, and SCFAs of 6 carbons or more are non-agonists and have odors that are more […]
Read MoreA patent filed on behalf of Takasago International Corp identifies OR2L3 as a receptor for α-terpineol, 4-terpineol, and 4-methyl acetophenone, with additional responses to indole and skatole. Identified as antagonists are cis-3-hexenyl hexanoate, Timberol, and Santaliff. While the agonists as a group may not seem to show an obvious pattern of an aroma note, the […]
Read MoreThese images list some of the ORs that are known to respond to each aroma, and which perceptual notes have been assigned to them. Lemon image by Ben Landers from Pixabay.Cinnamon image by Steve Buissinne from Pixabay.Clove image by abuyotam from Pixabay.Vanilla image by Lukas from Pexels.Caraway image by David Mark from Pixabay.
Read MoreVeithen et al (2015), writing about OR1D2’s broadly tuned agonist spectrum, claim that “the different agonists are not linked by a common organoleptic characteristic or note.” Here we present evidence, in the form of a differential experiment, to refute that statement. The following mixtures were prepared: 1.) tetrahydromyrcenol 0.6g, bourgeonal 15% in EtOH 0.9g, floralozone […]
Read MoreAfter finding that OR51E1 agonists have a cheesy note, the author has targeted three more receptors with agonist/antagonist differential experiments. For OR2A25, the aroma of unmixed geranyl acetate was compared with that of the same compound mixed with methyl salicylate. Geranyl acetate is an agonist for OR2A25. Methyl salicylate is an antagonist for this receptor, […]
Read MoreOR51E1 is a receptor for fatty acids with 3-10 carbon atoms, particularly those with cheesy or sweaty perceptual notes. But this receptor is also sensitive to methyl eugenol, methyl salicylate, and menthol, none of which smell cheesy or sweaty. Previously it was hypothesized on the PrimaryOdors website that OR51E1 must encode a milky quality, since […]
Read MoreA dissertation by Kang (2000) details results of OR-ligand assays for indole, Hedione, and naphthalene. The data show each molecule generating responses in a widespread, discontinuous, random-looking array of odorant receptors. Most of these receptors had not previously been deorphaned, and indeed assays typically suffer from some ORs failing to express on the cell surface […]
Read MoreFrançoise et al ([1], [2]) have identified OR2AG1 as a receptor associated with green pea, beany, grassy, galbanum, and bell pepper aroma characters of substituted pyrazines. This class of aroma compounds tends to have nutty, earthy, cacao, roasty, and potato type odors, and the compounds are almost all OR5K1 agonists (Marcinek et al, 2021), although […]
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