title: OR2M3: A Highly Specific and Narrowly Tuned Human Odorant Receptor for the Sensitive Detection of Onion Key Food Odorant 3-Mercapto-2-methylpentan-1-ol.
abstract: The detection of key food odorants appears to be an important capability of odorant receptors. Here, thiols occupy an outstanding position among the 230 known key food odorants because of their very low odor thresholds. Members of the homologous series of 3-mercapto-2-methylalkan-1-ols have been described as onion key food odorants or food constituents and are detected at logarithmically different thresholds. 3-Mercapto-2-methylpentan-1-ol being the only key food odorant within this series also has the lowest odor threshold. Most odorants typically activate combinations of odorant receptors, which may be narrowly or broadly tuned. Consequently, a specific receptor activation pattern will define an odor quality. In contrast, here we show that just 1 of the 391 human odorant receptors, OR2M3, responded exclusively to 3-mercapto-2-methylpentan-1-ol of the 190 key food odorants tested, with a half maximal effective concentration at submicromolar concentration. Moreover, neither the Denisovan OR2M3 nor the closest OR2M3 homologs from five species did respond to this compound. This outstanding specificity of extremely narrowly tuned human OR2M3 can explain both odor qualities and odor threshold trend within a homologous series of 3-mercapto-2-methylalkan-1-ols and suggests a modern human-specific, food-related function of OR2M3 in detecting a single onion key food odorant.
authors.affiliation: Deutsche Forschungsanstalt für Lebensmittelchemie, Leibniz Institut, Lise-Meitner-Str. 34, D-85354 Freising, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Noe
authors.affiliation: Institut für Lebensmittelchemie, Technischen Universität München, Lise-Meitner-Str. 34, D-85354 Freising, Germany and.|Present adress: Nestlé Product Technology Centre, Lebensmittelforschung GmbH, Lange Straße 21, D-78224 Singen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Polster
authors.affiliation: Deutsche Forschungsanstalt für Lebensmittelchemie, Leibniz Institut, Lise-Meitner-Str. 34, D-85354 Freising, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Geithe
authors.affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Auf dem Aberg 1, D-57392 Schmallenberg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Kotthoff
authors.affiliation: Institut für Lebensmittelchemie, Technischen Universität München, Lise-Meitner-Str. 34, D-85354 Freising, Germany and.
authors.forename: Peter
authors.initials: P
authors.lastname: Schieberle
authors.affiliation: Deutsche Forschungsanstalt für Lebensmittelchemie, Leibniz Institut, Lise-Meitner-Str. 34, D-85354 Freising, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Krautwurst
mesh_terms: D002478:Cells, Cultured; D006801:Humans; D015394:Molecular Structure; D009812:Odorants / Q000032:analysis*; D019697:Onions / Q000737:chemistry*; D000439:Pentanols / Q000032:analysis* / Q000737:chemistry; D018035:Receptors, Odorant / Q000378:metabolism*; D012903:Smell; D013438:Sulfhydryl Compounds / Q000032:analysis* / Q000737:chemistry
chemical_list: C000601325:OR2W3 protein, human; D000439:Pentanols; D018035:Receptors, Odorant; D013438:Sulfhydryl Compounds; C406689:3-mercapto-2-methylpentan-1-ol
keywords: G protein-coupled receptor; Neanderthal; chemosensory; olfaction; thiol