Beyond the Active Site: First‐In‐Class Leishmania Infantum Trypanothione Reductase Dimerization Disruptors as Antileishmanial Leads

Leishmania infantum trypanothione reductase (Li‐TryR) is an essential enzyme for parasite redox homeostasis and a validated target for antileishmanial therapy. Classical inhibitors acting at the active site have shown limited success due to poor selectivity, suboptimal pharmacological properties, and lack of in‐cell efficacy. This work presents a comprehensive strategy to develop first‐in‐class Li‐TryR dimerization disruptors, targeting the protein–protein interface required for enzymatic activity. Through molecular modeling, mutagenesis, and structural analysis, a key α‐helical hotspot (around residue E436) was identified as a druggable region. Interface‐derived peptides, helix‐stabilized stapled analogs, α/β‐foldamers, and cell‐penetrating conjugates demonstrated that dimer disruption effectively inhibits LiTryR and can translate into antiparasitic activity. Building on these insights, several families of small‐molecule proteomimetics, including imidazole‐phenyl‐thiazoles, triazole analogs, and triazolium salts, were developed, achieving low‐micromolar to submicromolar inhibition and significant activity in parasite cultures and intracellular models. Overall, this work establishes dimer‐interface targeting as a novel therapeutic paradigm for leishmaniasis and provides multiple optimized chemical scaffolds for future drug development.