Investigation of angiotensin-I-converting enzyme (ACE) inhibitory tri-peptides: a combination of 3D-QSAR and molecular docking simulations

Figures

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  Fig. 1. (A) Structure of compound 18 used as a template for template ligand-based alignment; (B) the alignment for ACE from the template ligand-based alignment.

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  Fig. 2. The correlation plots of the actual versus the predicted pIC50 values using the training set based on the CoMFA and CoMSIA models obtained from the activity for ACE.

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  Fig. 3. CoMFA StDev × Coeff contour plots for ACE inhibitors in combination of compound 18. (A) The steric contour map, where the green and yellow contours represent 80% and 20% level contributions, respectively. (B) The electrostatic contour map, where the blue and red contours represent 80% and 20% level contributions, respectively.

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  Fig. 4. CoMSIA StDev × Coeff contour plots for ACE inhibitors in combination of compound 18. (A) The steric contour map, where the green and yellow contours represent 80% and 20% level contributions, respectively. (B) The electrostatic contour map, where the blue and red contours represent 80% and 20% level contributions, respectively. (C) The hydrogen bond donor contour map, where the cyan and purple contours represent 80% and 20% level contributions, respectively. (D) The hydrogen bond acceptor contour map, where the magenta and red contours represent 80% and 20% level contributions, respectively.

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  Fig. 5. (A) The active site amino acid residues around compound 18. (B) The enlargement for the ligand in the binding site after molecular docking, which is displayed in stick, H-bonds are shown as dotted black lines, and the nonpolar hydrogens were removed for clarity.

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  Fig. 6. (A) The active site amino acid residues around compound 4. (B) The enlargement for the ligand in the binding site after molecular docking, which is displayed in stick, H-bonds are shown as dotted black lines, and the nonpolar hydrogens were removed for clarity.

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  Fig. 7. Structural superposition of 3BKK-18 and 3BKK-4. The projection highlights the structure of the active site with compound 18 (green) and 4 (cyan), which are displayed in sticks.

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  Fig. 8. Structure–activity relationship revealed by QSAR studies for ACE peptides.