Novel ACE inhibitory tripeptides from ovotransferrin using bioinformatics and peptidomics approaches

Abstract

Food-derived ACE inhibitory peptides have recently attracted increased attention. This work focused on a more efficient in silico method to find ACE inhibitory peptides from ovotransferrin. In this work, ovotransferrin was digested into peptides by virtual enzymolysis. Subsequently, in vitro ACE inhibitory activity of potential tripeptides was conducted following the peptide score, toxicity, and water solubility prediction. Both pharmacophore study and flexible docking were applied to analyze ACE inhibition mechanism of tripeptides. Our results demonstrated that EWL was a potent ACE inhibitory tripeptide with IC₅₀ value of 380 ± 10 μM. Besides, pharmacophore and flexible docking showed that the pi interaction and hydrogen bond were the key interactions in ACE-EWL complex. It appears that the in vitro ACE inhibitory activity of tripeptide EWL was consistent with its molecular modeling.

Figure 1

Effect of EWL on HepG₂ cells. Cells were treated with EWL at the indicated concentrations (0.1, 0.25, 0.5, 1 and 2 mM), cell viability was assessed by the MTT assay. *p < 0.05 compared with the control group.

Figure 2

Elite pharmacophore model generated based on EWL and KDF: (a) Pharmacophore-3 model. (b) Mapping of the tripeptide EWL to pharmacophore-3. (c) Mapping of the tripeptide KDF to pharmacophore-1. (Purple ball stand for HBD feature, blue ball stand for negative charge, azure ball stand for hydrophobic feature, red ball stand for positive charge).

Figure 3

3D (a) and 2D (b) diagram of interactions of EWL-ACE complex. Green dash line represent conventional hydrogen bond, brown dash line represent attractive charge, violet dash line represent pi interaction, indigo dash line represent carbon hydrogen bond, and red dash line represent unfavorable charge.

Figure 4

3D (a) and 2D (b) diagram of interactions of KDF-ACE complex. Green dash line represent conventional hydrogen bond, brown dash line represent attractive charge, violet dash line represent pi interaction, indigo dash line represent carbon hydrogen bond.

Figure 5

Ligand interaction of lisinopril-ACE complex in 3D (a) and 2D (b) diagram. Green dash line represents conventional hydrogen bond, brown dash line represents attractive charge, violet dash line represents pi interaction, and indigo dash line represents carbon hydrogen bond.