IN SILICO IDENTIFICATION OF POTENTIAL Plasmodium falciparum ACETYL-COA SYNTHETASE (PfACS) INHIBITORS USING DRUG REPURPOSING APPROACH

Abstract

The persistent rise in malaria-related deaths among children and pregnant women underscores the ongoing global health challenge posed by this disease. Although preventive activities and first-line treatment options (which include artemisinin-based combination therapies) have been extensively used, the swift development of drug-resistant Plasmodium falciparum isolates has left malaria control efforts severely impaired. Drug repurposing provides an economical alternative to traditional drug discovery approaches by uncovering novel therapeutic uses for existing drugs with well-characterized safety profiles. This study focuses on Plasmodium falciparum acetyl-CoA synthetase (PfACS), an essential enzyme involved in acetate metabolism and histone acetylation, as a potential antimalarial drug target. Its structural divergence from human isoforms increases its likelihood of selective inhibition, with the lowest potential to induce toxicity in the host. A multistage computational drug repurposing workflow was employed to identify FDA-approved inhibitors of PfACS. Structural analysis identified the crystal structure of Coccidioides immitis acetyl-CoA synthetase (PDB: 7KQ6) as the most suitable template for PfACS modeling. The AlphaFold2-predicted PfACS structure was also validated. A library of 12,718 DrugBank compounds was sequentially selected using Lipinski’s Rule of Five and the Ersilia eos80ch machine-learning antiplasmodial activity model, yielding a dataset of 377 biologically enriched compounds. Molecular docking, binding free-energy estimation (MM/GBSA), pharmacophoric interaction analysis, and density functional theory (DFT) calculations and Molecular Dynamics (MD) Simulation were subsequently performed. Four lead compounds (Hit 01–04) demonstrated favorable binding affinity, interaction similarity with the reference inhibitor MMV693183, and supportive electronic reactivity profiles, with promising potential as PfACS inhibitors and antimalarial agents.