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
101 OR2L5 Human 312 1 2 L Q8NG80 KP290689 0 View
102 OR2L6P Human 1 2 L NG_004274 0 View
103 OR2L8 Human 312 1 2 L Q8NGY9 NM_001001963 0 View
104 OR2L9P Human 1 2 L NG_004273 0 View
105 OR2M1P Human 1 2 M NR_002141 0 View
106 OR2M2 Human 347 1 2 M Q96R28 NM_001004688 1 View
107 OR2M3 Human 312 1 2 M Q8NG83 KP290147 0 View
108 OR2M4 Human 311 1 2 M Q96R27 KP290146 5 View
109 OR2M5 Human 312 1 2 M A3KFT3 NM_001004690 0 View
110 OR2M7 Human 312 1 2 M Q8NG81 NM_001004691 4 View
111 OR2N1P Human 6 2 N NG_002216 0 View
112 OR2P1P Human 6 2 P NG_004693 0 View
113 OR2Q1P Human 7 2 Q NG_004310 0 View
114 OR2R1P Human 7 2 R NG_004373 0 View
115 OR2S1 Human 9 2 S NG_004379 0 View
116 OR2S2 Human 319 9 2 S Q9NQN1 NM_019897 0 View
117 OR2T1 Human 369 1 2 T O43869 NM_030904 3 View
118 OR2T10 Human 312 1 2 T Q8NGZ9 NM_001004693 4 View
119 OR2T11 Human 316 1 2 T Q8NH01 KP290144 0 View
120 OR2T12 Human 320 1 2 T Q8NG77 NM_001004692 0 View
121 OR2T2 Human 324 1 2 T Q6IF00 KP290582 0 View
122 OR2T27 Human 317 1 2 T Q8NH04 NM_001001824 0 View
123 OR2T29 Human 315 1 2 T Q8NH02 NM_001004694 0 View
124 OR2T3 Human 318 1 2 T Q8NH03 NM_001005495 0 View
125 OR2T32P Human 1 2 T NG_004411 0 View
Showing 101 to 125 of total 2067 entries