OlfactionBase: A repository of Odors, Odorants, Olfactory Receptors and related information
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Receptors

Olfactory Receptors (ORs) are the physical barriers between the environment and the brain. ORs are members of the GPCR-rhodopsin family, which is involved in cell recognition, signal transduction activation, and sense mediation. OR is made up of seven transmembrane (TM) helical domains bound by three putative extracellular loops (EL) and three putative intracellular loops (IL), an extracellular N-terminus, and an intracellular C-terminus. At the intersection of TM3 and IL2, the intracellular loop includes a conserved sequence motif, the aspartate-arginine-tyrosine (DRY) amino acid motif, which is a hallmark of GPCRs. The TM1, TM2, and TM7 are all conserved. The binding site specificity is determined by the amino acid side chains of the central TM domains, which are structurally diverse. The binding pocket of ORs has a hydrophobic environment, indicative of hydrophobic interactions between odorants and ORs. The binding specificity of ORs is influenced not only by the central TM-domains hyper-variable region, but also by the N-termini and C-termini. Both terminals are small, with only about 20 amino acids each. The conserved cysteine residues in the EL1 and EL2-loops are involved in inter- and intramolecular disulphide linkages. One of the three cysteine restudies in EL2-loop has a specific role. A metal binding site is formed by the sequence motif (HXXC[DE]) in EL2-loop. On binding with Zn(II) or Cu, the EL2-loop transforms into a -helical structure confirmation (eighth helix) (II).When an odorant with a high affinity for metal ions replaces one of the metal-ligated amino acids in the EL2-loop, ORs undergo structural rearrangement, which is necessary for the activation of G-olf proteins attached to OR receptors. On the cytoplasmic side of the TM domains, the sequence motifs KAFSTC, PMYFFL, and YRDYAM play a role in OR folding and activation. The amino acid residues on the extracellular side of TM domains are variable, indicating a wide range of possible odorant recognition sites.

OlfactionBase lists 2067 ORs from two species (Human (851) and Mus musculus (1216)).

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Sr. No Receptor Organism Length Chromosome Family Sub Family UniProt GenBank #Odorants Details
76 OR2C1 Human 312 16 2 C O95371 KP290588 5 View
77 OR2C3 Human 320 1 2 C Q8N628 NM_198074 0 View
78 OR2D2 Human 308 11 2 D Q9H210 NM_003700 0 View
79 OR2D3 Human 330 11 2 D Q8NGH3 KP290410 0 View
80 OR2E1P Human 6 2 E NG_004088 0 View
81 OR2F1 Human 317 7 2 F Q13607 KP290641 1 View
82 OR2F2 Human 317 7 2 F O95006 NM_001004685 0 View
83 OR2G1P Human 6 2 G NG_004689 0 View
84 OR2G2 Human 317 1 2 G Q8NGZ5 NM_001001915 3 View
85 OR2G3 Human 309 1 2 G Q8NGZ4 NM_001001914 0 View
86 OR2G6 Human 316 1 2 G Q5TZ20 KP290511 0 View
87 OR2H1 Human 316 6 2 H Q9GZK4 KP290422 0 View
88 OR2H2 Human 312 6 2 H O95918 KP290159 0 View
89 OR2H4P Human 6 2 H NG_004685 0 View
90 OR2H5P Human 6 2 H NG_002319 0 View
91 OR2I1P Human 316 6 2 I Q8NGU4 NG_004688 0 View
92 OR2J1 Human 312 6 2 J Q9GZK6 NM_001348294 1 View
93 OR2J2 Human 312 6 2 J O76002 NM_030905 10 View
94 OR2J3 Human 311 6 2 J O76001 KP290732 5 View
95 OR2J4P Human 6 2 J NG_004684 0 View
96 OR2K2 Human 316 9 2 K Q8NGT1 NM_205859 0 View
97 OR2L13 Human 312 1 2 L Q8N349 KP290505 0 View
98 OR2L1P Human 1 2 L NR_002145 0 View
99 OR2L2 Human 312 1 2 L Q8NH16 KP290490 0 View
100 OR2L3 Human 312 1 2 L Q8NG85 KP290550 0 View
Showing 76 to 100 of total 2067 entries