Docking and quantitative structure–activity relationship of bi-cyclic heteroaromatic pyridazinone and pyrazolone derivatives as phosphodiesterase 3A (PDE3A) inhibitors
Fig 2
Superposition of PDE3A model (pale orange) to the PDE3B crystal structure (cyan).
(a) Protein structure visualization presenting modeled loops (L1 and L2), and the location of metal and ligand binding site. (b) Comparison of PDE 3A/3B active sites; tertiary protein structure is shown in ribbons, relevant protein residues and water molecules are shown as thick tubes, magnesium ions are shown as van der Waals spheres, and ligands are shown in ball-and-stick representation; dotted lines indicate zero-order bonds, dashed black lines represent H-bonds, and cyan dashed lines indicate π-stacking interactions. Carbon coloring are: cyan and light blue for protein and ligand atoms in the PDE3B crystal, and pale orange and orange for protein and ligand atoms in the PDE3A model.