Structure-Based Discovery of Non-Covalent Triazole-Based Cruzipain Inhibitors with Improved Bioactivity Translation.

Area of Science:

• Medicinal Chemistry
• Parasitology
• Computational Biology

Background:

• Chagas disease, a neglected tropical illness, lacks effective treatments, necessitating novel antichagasic drugs.
• Cruzipain (CZP), a cysteine protease from *Trypanosoma cruzi*, is a validated therapeutic target, but potent inhibition remains difficult.

Purpose of the Study:

• To design and synthesize novel triazole-based noncovalent inhibitors targeting cruzipain (CZP).
• To evaluate the potency of these inhibitors against isolated CZP and their trypanocidal activity in cellular models.
• To elucidate structure-activity relationships (SAR) and understand molecular determinants for effective Chagas disease therapy.

Main Methods:

• Utilized state-of-the-art molecular modeling, including molecular docking, molecular dynamics simulations, and binding free-energy calculations.
• Synthesized and characterized a series of novel 1,2,3-triazole derivatives.
• Assessed enzymatic inhibition of CZP and antiparasitic activity against *Trypanosoma cruzi*.

Main Results:

• Identified potent triazole-based noncovalent inhibitors of CZP with significant trypanocidal activity.
• Elucidated key structure-activity relationships, linking enzymatic inhibition to cellular effects.
• Discovered conserved interaction patterns in CZP's active site (oxyanion hole, S1/S1' subsites) crucial for inhibitor efficacy.

Conclusions:

• Developed promising 1,2,3-triazole-based antichagasic candidates.
• Clarified molecular factors governing the translation of enzyme inhibition to cellular activity.
• Established a predictive framework for the rational design of CZP-targeted inhibitors for Chagas disease treatment.