Abstract

Trypanothione synthetase (TryS) produces N¹,N⁸-bis(glutathionyl)spermidine (or trypanothione) at the expense of ATP. Trypanothione is a metabolite unique and essential for survival and drug-resistance of trypanosomatid parasites. In this study, we report the mechanistic and biological characterisation of optimised N⁵-substituted paullone analogues with anti-TryS activity. Several of the new derivatives retained submicromolar IC₅₀ against leishmanial TryS. The binding mode to TryS of the most potent paullones has been revealed by means of kinetic, biophysical and molecular modelling approaches. A subset of analogues showed an improved potency (EC₅₀ 0.5–10 µM) and selectivity (20–35) against the clinically relevant stage of Leishmania braziliensis (mucocutaneous leishmaniasis) and L. infantum (visceral leishmaniasis). For a selected derivative, the mode of action involved intracellular depletion of trypanothione. Our findings shed light on the molecular interaction of TryS with rationally designed inhibitors and disclose a new set of compounds with on-target activity against different Leishmania species.

摘要

锥虫硫醇合成酶（TryS）以ATP为代价产生N ¹ ，N ^8-双（谷胱甘肽）亚精胺（或锥虫硫酮）。锥虫硫醇是独特的代谢产物，对于锥虫的寄生虫的存活和耐药性至关重要。在这项研究中，我们报告了具有抗TryS活性的优化的N ⁵取代的paullone类似物的力学和生物学特性。几种新的衍生物保留了抗利什曼虫TryS的亚微摩尔IC ₅₀。已通过动力学，生物物理和分子建模方法揭示了最有效的paullones与TryS的结合模式。一部分类似物显示出更高的效价（EC ₅₀对巴西利什曼原虫（粘膜皮肤利什曼病）和婴儿利什曼原虫（内脏利什曼病）的临床相关阶段的选择性为0.5–10 µM，选择性为（20–35 ）。对于选定的衍生物，作用方式涉及锥虫硫磷的细胞内消耗。我们的发现揭示了TryS与合理设计的抑制剂之间的分子相互作用，并揭示了针对不同利什曼原虫物种具有针对性活性的新化合物。