Interaction mechanism of egg derived peptides RVPSL and QIGLF with dipalmitoyl phosphatidylcholine membrane: microcalorimetric and molecular dynamics simulation studies.

BACKGROUND: Egg-derived peptides are becoming increasingly popular due to their biological activity and non-toxic effects. The egg-derived peptides Arg-Val-Pro-Ser-Leu (RVPSL) and Gln-Ile-Gly-Leu-Phe (QIGLF) display strong angiotensin-converting enzyme inhibitory activity and they can be taken up by intestinal epithelial cells. The interaction of the egg-derived peptides RVPSL and QIGLF with the membrane remains unclear. RESULTS: The position and structure of the peptides in the membrane were calculated. The maximum density values of RVPSL and QIGLF were 2.27 and 1.22 nm from the center of the 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) membrane, respectively, indicating that peptides penetrated the membrane-water interface and were embedded in the membrane. The interaction of RVPSL and QIGLF with the DPPC membrane did not affect the average area per lipid or the lipid sequence parameters. The thermodynamic parameters ΔH, ΔG, and ΔS of the interaction between the peptide RVPSL with the DPPC membrane were 17.91 kJ mol-1 , -17.63 kJ mol-1 , 187.5 J mol-1 ·k-1 , respectively. The thermodynamic parameters ΔH, ΔG, and ΔS of the interaction between peptide QIGLF with DPPC membrane were 17.10 kJ mol-1 , -17.12 kJ mol-1 , 114.8 J mol-1 ·k-1 , respectively. CONCLUSION: The results indicated that the binding of peptides RVPSL and QIGLF to DPPC is an endothermic, spontaneous, and entropy-driven reaction. The results of the study are relevant to the problem of the low bioavailability of bioactive peptides (BP). © 2023 Society of Chemical Industry.

Interaction mechanism of three egg protein derived ACE inhibitory tri-peptides and DPPC membrane using FS, FTIR, and DSC studies.

Understanding the interaction of food derived angiotensin converting enzyme (ACE) inhibitory peptides and intestinal epithelial cell membrane may help to improve their absorption. This research aimed to study the molecular interaction of ACE inhibitory tri-peptides ADF, FGR, and MIR with DPPC membrane during absorption process. The DPPC liposome was prepared and characterized, then used as a model membrane. The permeability of tri-peptides across the membrane was investigated using Fluorescence spectroscopy. The effect of tri-peptides on the structure and dynamics of DPPC bilayers was determined using Fourier transform infrared spectroscopy. The effect of tri-peptides on the phase transition temperature in the DPPC membrane was also analyzed using Differential scanning calorimetry. The results showed that ACE inhibitory tri-peptides ADF, FGR, and MIR can penetrate into both the membrane-water interface and hydrophobic region of DPPC bilayer, and the tri-peptide FGR have higher permeability across the membrane.

Identification of tuna protein-derived peptides as potent SARS-CoV-2 inhibitors via molecular docking and molecular dynamic simulation.

The present study aimed to identify potential SARS-CoV-2 inhibitory peptides from tuna protein by virtual screening. The molecular docking was performed to elicit the interaction mechanism between targets (Mpro and ACE2) and peptides. As a result, a potential antiviral peptide EEAGGATAAQIEM (E-M) was identified. Molecular docking analysis revealed that E-M could interact with residues Thr190, Thr25, Thr26, Ala191, Leu50, Met165, Gln189, Glu166, His164, His41, Cys145, Gly143, and Asn119 of Mpro via 11 conventional hydrogen bonds, 9 carbon hydrogen bonds, and one alkyl interaction. The formation of hydrogen bonds between peptide E-M and the residues Gly143 and Gln189 of Mpro may play important roles in inhibiting the activity of Mpro. Besides, E-M could bind with the residues His34, Phe28, Thr27, Ala36, Asp355, Glu37, Gln24, Ser19, Tyr83, and Tyr41 of ACE2. Hydrogen bonds and electrostatic interactions may play vital roles in blocking the receptor ACE2 binding with SARS-CoV-2.

Identification and molecular docking of peptides from Mizuhopecten yessoensis myosin as human bitter taste receptor T2R14 blockers.

Bitter taste receptor 14(T2R14) is one of the most widely regulated bitter taste receptors (T2Rs) and plays a vital role in the research of T2R blockers. In this study, potential T2R14 blockers were identified from the myosin of Mizuhopecten yessoensis. Myosin was hydrolyzed in silico by gastrointestinal proteases, and the peptides were obtained. The peptides' biological activity, solubility, and toxicity were predicted, and the potential T2R14 blocking peptides were docked with T2R14. Subsequently, the in vitro T2R14 blocking activity of the selected peptide was verified by an electronic tongue. The results showed that QRPR had T2R14 blocking activity with an IC50 value of 256.69 ± 1.91 µM. Molecular docking analysis suggested the key role of the amino residues Asp168, Leu178, Asn157, and Ile262 in blocking T2R14, and revealed that the amino acid residues of T2R14 bound with the peptide QRPR via electrostatic interaction, hydrophobic interaction, conventional hydrogen bond, and hydrogen bond. The novel T2R14 blocking peptide QRPR is a potential candidate for suppressing bitterness.

Identification and molecular docking study of fish roe-derived peptides as potent BACE 1, AChE, and BChE inhibitors.

Acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and beta-secretase 1 (BACE 1) play vital roles in the development and progression of Alzheimer's disease (AD). The objective of the present study was to identify fish roe-derived anti-AD peptides with activities against AChE, BChE, and BACE 1. Fish roe proteins were cleaved in silico by gastrointestinal proteases, and the released peptides were collected. Subsequently, the toxicity, solubility, and biological properties of these novel di- and tri-peptides were predicted and validated. Finally, potential anti-AD peptides were docked to targets, i.e., AChE, BChE, and BACE 1. A novel anti-AD tripeptide WIR with potent inhibition of AChE and BACE 1 was identified, with IC50 values of 43.32 ± 1.22 µM and 2.27 ± 0.35 mM, respectively. In addition, the inhibition rate of WIR (at a concentration of 1.06 ± 0.87 µM) against BChE was 33.5%, and the peptide WIR was able to simultaneously interact with AChE, BChE, and BACE 1. Residues Ser286 of AChE, Asp70 of BChE, and Thr231, Arg235 of BACE 1 played key roles in the interaction with peptide WIR. In summary, peptide WIR exhibits the potential to be an effective treatment for AD.