Fig. 4.

Hierarchical clustering of Olfr73 agonist molecules. Six different classes of agonists are identified (distinguished by a color code) according to their PH4 features. In the Hierarchical diagram, the links between the chemical compounds are represented as branched vertical lines. The height of the lines, coupled with merging distance (numbers showed in each node), indicate the normalized dissimilarity distance between the adjacent compounds. A higher line or a larger merging distance denotes a larger dissimilarity. A typical representative molecular structure of each class is shown below the dendrogram together with their molecular surfaces indicating hydrophobic moieties in grey and polar moieties in red. The commonly shared atoms within a certain class of molecules are labeled with colored dots accordingly. The molecular structures of the six classes of agonists are grouped in boxes. The 17 newly found agonists are represented as A1-A17 in blue. The 25 previously reported agonists are represented as B1-B25 in black. The agonist isoeugenol is B3 and p-isobutylphenol is A1. In all cases the corresponding micromolar EC₅₀ values are indicated in brackets. Names of A- and B-compounds are listed in Supplementary Tables 2 and 3