Figure 1.
Chymase-dependent conversion of angiotensin I to angiotensin II and precursors of TGF-β and MMP-9 to their active forms.
Figure 2.
Overall 3D structure of human chymase and the zoomed view which clearly shows the important catalytic residues.
Figure 3.
The 2D chemical structures of human chymase inhibitors used in this study along with their IC50values.
Figure 4.
The RMSD plot to investigate the stability of the systems.
Figure 5.
The RMSF plots of all systems (A) full protein and (B) important active site residues.
Figure 6.
Overlay of the binding modes of the substrate and all the inhibitors at the active site of human chymase enzyme.
The Ang I, C1, C2, and C3 complexes were represented in orange, cyan, violet, and splitpea green colors, respectively.
Figure 7.
Active site of the substrate (Ang I) complex of the enzyme.
(A) Amino acid residues and bound substrate are shown in thin stick and ball-stick forms, respectively. Residues of substrate are shown in red color and labeled in blue color. Hydrogen bonds are shown in black dashed lines. (B) The structural changes observed between the active site regions of apoform (grey) and human chymase-substrate complex (orange). The amino acid residues are shown in thin stick form. Only polar hydrogen atoms are added for clarity.
Figure 8.
Intermolecular hydrogen bond plots.
Observed intermolecular hydrogen bonds between (A) the substrate (B) inhibitors and active site residues.
Figure 9.
Binding modes and molecular interactions of the three inhibitors.
(A) Overlay of the binding modes of all the inhibitors at the active site of human chymase enzyme. (B) C1 in cyan (C) C2 in violet (D) C3 in splitpea green colors at the active site of enzyme. The hydrogen bond and π-interactions were displayed in black dashed and brown solid lines, respectively. Amino acid residues and inhibitors are shown in stick and ball-stick forms whereas the gray, cyan, violet, and splitpea green cartoons represent apoform of enzyme, C13, C14, and C15 complexes, respectively. Only polar hydrogen atoms are added for clarity.
Table 1.
Calculated non-bonded interaction energies between the inhibitors and important active site residues.
Figure 10.
Development of hybrid pharmacophore model.
The key pharmacophoric features generated from the binding modes of (A) C1 and (B) Ang I. The amino acid residues of the enzyme are shown in gray thin stick form whereas the bound C1 and Ang I are shown in thick stick form. The secondary structure cartoon of the enzyme is colored based on the hydrophobicity of the amino acid residues. (C) Final hybrid pharmacophore model (D) Hybrid pharmacophore model with distance constraints.
Figure 11.
Overlay of the docked pose (green) of inhibitor with its crystal structure conformation (gray).
Figure 12.
The 2D chemical structures of the final identified hit compounds.
Table 2.
Results of molecular docking using GOLD and Autodock programs along with electronic parameters calculated for the known inhibitors and hit compounds.
Figure 13.
The binding modes of (A) Hit 1 (B) Hit 2 (C) Hit 3 and (D) Hit 4 at the active site of the enzyme. The amino acid residues and bound ligands are shown in stick representations. The hydrogen bond, and π-interactions are shown in black dashed, and brown solid lines. Only polar hydrogen atoms are added for clarity.