Figure 1.
The four A1AR models used in this study.
Helices are labeled with Roman numerals. For clarity, individual residues mentioned in the text, depicted as thick sticks, are only labeled in panel A. Additional residues that were optimized are in thin sticks, including Lys1684.99, Glu170, Lys173, and Met177. Helices I and II have been removed for clarity. The X-ray crystallographic structure of the A2AAR, the template (PDB 3EML), is shown in black.
Table 1.
In vitro affinity in binding to three subtypes of hARs of diverse heterocyclic derivatives identified through their high ranks in the in silico screen (structures are shown in Chart 2).
Figure 2.
Calculated binding mode of compound 8, the ligand hit with the highest selectivity towards A1AR.
The protein is model A. Orange dotted lines denote hydrogen bonds formed with Asn2546.55. Helices are labeled with roman numerals.
Table 2.
Performance of the four homology models against the three AR subtypes.
Figure 3.
Comparing the selectivity of ligands from this work with ChEMBL data.
Selectivity statistics for experimentally measured affinities of molecules from the ChEMBL database (outer shell) and our screen (inner donut). Selectivity ratios have been binned into log-sized bins, ranging from more than 1000-fold selectivity in either direction to 1.
Figure 4.
Reference compounds (known selective A1AR antagonists) mentioned in the text. Ki values are as follows, with targets other than human A1AR in parentheses: 1: Ki 0.8 nM [8]; 2: Ki 18 nM; 3: Ki 1 nM; 4: Ki 1 nM [11]; 5: Ki 3 nM (bovine A1AR [20]); 6: Ki 584 nM [21].
Figure 5.
Molecules identified in this study. Binding affinity data at three AR subtypes are presented in Table 1.