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
126 OR2T33 Human 320 1 2 T Q8NG76 NM_001004695 0 View
127 OR2T34 Human 318 1 2 T Q8NGX1 NM_001001821 4 View
128 OR2T35 Human 323 1 2 T Q8NGX2 NM_001001827 0 View
129 OR2T4 Human 348 1 2 T Q8NH00 NM_001004696 0 View
130 OR2T5 Human 315 1 2 T Q6IEZ7 NM_001004697 0 View
131 OR2T6 Human 308 1 2 T Q8NHC8 NM_001005471 0 View
132 OR2T7 Human 308 1 2 T P0C7T2 NM_001386051 0 View
133 OR2T8 Human 312 1 2 T A6NH00 KP290593 0 View
134 OR2U1P Human 6 2 U NG_004625 0 View
135 OR2U2P Human 6 2 U NG_004687 0 View
136 OR2V1 Human 315 5 2 V Q8NHB1 NM_001258283 0 View
137 OR2V2 Human 315 5 2 V Q96R30 KP290150 0 View
138 OR2W1 Human 320 6 2 W Q9Y3N9 KP290589 39 View
139 OR2W2P Human 6 2 W NG_004279 0 View
140 OR2W3 Human 314 1 2 W Q7Z3T1 NM_001001957 0 View
141 OR2W4P Human 6 2 W NG_004261 0 View
142 OR2W5 Human 320 1 2 W A6NFC9 KP290530 0 View
143 OR2W6P Human 318 6 2 W Q8NHA6 NG_004260 0 View
144 OR2X1P Human 1 2 X NG_004412 0 View
145 OR2Y1 Human 311 5 2 Y Q8NGV0 NM_001001657 0 View
146 OR2Z1 Human 314 19 2 Z Q8NG97 NM_001004699 0 View
147 OR3A1 Human 315 17 3 A P47881 KP290644 9 View
148 OR3A2 Human 321 17 3 A P47893 KP290345 0 View
149 OR3A3 Human 321 17 3 A P47888 KP290571 0 View
150 OR3A4 Human 348 17 3 A P47883 KP290572 0 View
Showing 126 to 150 of total 2067 entries