Fig. 1.

Conserved motifs in class I and class II human ORs and comparison with non-olfactory class A GPCRs. a Logos summarize the conservation amongst 397 human OR sequences (58 are class I ORs and 339 are class II) and 204 non-olfactory class A GPCRs [10, 27]. Major differences are underlined in blue. b Highest conservation of class-specific motifs in TM3, TM5, TM6, and TM7. c Three class I human OR structures (representative of each class I subgroup) show the position of conserved motifs in YGL^TM5 (blue) and HRFG^TM6 (in red). Both motifs are predicted to face each other; in these representations, intra- and extra-cellular loops are omitted for image clarity