Identification of novel peptide inhibitors of Plasmodium falciparum dihydrofolate reductase (PfDHFR): molecular docking and MD simulation studies

Abstract

The presence of drug-resistant variants of Plasmodium parasites within the population has presented a substantial obstacle to the eradication of Malaria. As a result, numerous research groups have directed their efforts towards creating new medication candidates that specifically target parasites. In this study, our main objective was to identify tri-peptide inhibitors for Plasmodium falciparum Dihydrofolate Reductase (PfDHFR) with the aim of finding a new peptide that exhibits superior binding properties compared to the current inhibitor, WR99210. In order to achieve this objective, a virtual library consisting of 8000 tripeptides was generated and subjected to computational screening against wild-type PfDHFR. The purpose of this screening was to discover the most effective binders at the active site. The four most optimal tripeptides identified (Trp-Trp-Glu, Trp-Phe-Tyr, Phe-Trp-Trp, Tyr-Trp-Trp) exhibited significant non-covalent interactions inside the active site of PfDHFR and had binding energies ranging from −9.5 to −9.0 kcal/mol and WR99210 had a binding energy of −6.2 kcal/mol. A 250 ns Molecular Dynamics (MD) simulation was performed to investigate the kinetic and thermodynamic characteristics of the protein-ligand complexes. The Root Mean Square Deviation (RMSD) values for the optimal tripeptides fell within the allowed range, indicating the stability of the ligands inside the protein complex. The K_i value for the most effective tripeptide was 0.3482 µM, whereas WR99210 had a K_i value of 1.02 µM. This article presents the initial discovery of peptide inhibitors targeting PfDHFR. In this text, we provide a comprehensive explanation of the interactions that occur between peptides and the enzyme.

Communicated by Ramaswamy H. Sarma

Keywords:

• Molecular docking
• DFT
• peptide inhibitor
• malaria
• molecular dynamics simulation

Acknowledgments

KD thanks CSIR, New Delhi for the junior research fellowship. AC acknowledges the Department of Health Research (DHR), New Delhi, for financial assistance [R.12014/30/2022]. VK thanks UGC, New Delhi for the junior research fellowship.

Disclosure statement

The authors state no competing interest to declare for the presented work.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.