title: Structure of rat odorant-binding protein OBP1 at 1.6 A resolution.
abstract: The nasal mucosa is a specialist interfacial region sandwiched between the olfactory system and the gaseous chemical milieu. In mammals and insects, this region is rich in odorant-binding proteins that are thought to aid olfaction by assisting mass transfer of the many different organoleptic compounds that make up the olfactory landscape. However, in mammals at least, our grasp on the exact function of odorant-binding proteins is tentative and better insight into the role of these proteins is warranted, not least because of their apparent significance in the olfactory systems of insects. Here, the crystal structure of rat odorant-binding protein 1 is reported at 1.6 A resolution. This protein is one of the best-characterized mammalian odorant-binding proteins and only the third such protein structure to be solved at high resolution. The protein was crystallized in the holo form and contains an unidentifiable ligand that is probably an artefact from the Pichia pastoris expression system. Comparisons are made between this structure and a modelled OBP1 structure produced using the crystal structure of aphrodisin as a template. Comparisons are also made between OBP1 and the other two rat OBP subtypes, for which crystallographic data are unavailable. Interestingly, we also show that OBP1 is monomeric, which is in contrast to its previous assignment.
authors.affiliation: School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, England.
authors.forename: Scott A
authors.initials: SA
authors.lastname: White
authors.forename: Loïc
authors.initials: L
authors.lastname: Briand
authors.forename: David J
authors.initials: DJ
authors.lastname: Scott
authors.forename: Antoni J
authors.initials: AJ
authors.lastname: Borysik
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry; D054834:Lipocalins / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010675:Pheromones / Q000737:chemistry; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry; D051381:Rats / Q000378:metabolism*; D018035:Receptors, Odorant / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D004268:DNA-Binding Proteins; D054834:Lipocalins; C086608:OriP-binding protein 2; D010675:Pheromones; D011506:Proteins; D018035:Receptors, Odorant; D011993:Recombinant Fusion Proteins; C050082:aphrodisin protein, Mesocricetus auratus; C035737:major urinary proteins; C045648:odorant-binding protein