Molecular Modeling Section (MMS), Department of Pharmaceutical and Pharmacological Sciences, University of Padova, via Marzolo 5, 35131 Padova, Italy.
Laboratory Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo 11400, Uruguay.
Molecules. 2023 Jan 28;28(3):1276. doi: 10.3390/molecules28031276.
Trypanosoma brucei is a species of kinetoplastid causing sleeping sickness in humans and nagana in cows and horses. One of the peculiarities of this species of parasites is represented by their redox metabolism. One of the proteins involved in this redox machinery is the monothiol glutaredoxin 1 (1CGrx1) which is characterized by a unique disordered N-terminal extension exclusively conserved in trypanosomatids and other organisms. This region modulates the binding profile of the glutathione/trypanothione binding site, one of the functional regions of 1CGrx1. No endogenous ligands are known to bind this protein which does not present well-shaped binding sites, making it target particularly challenging to target. With the aim of targeting this peculiar system, we carried out two different screenings: (i) a fragment-based lead discovery campaign directed to the N-terminal as well as to the canonical binding site of 1CGrx1; (ii) a structure-based virtual screening directed to the 1CGrx1 canonical binding site. Here we report a small molecule that binds at the glutathione binding site in which the binding mode of the molecule was deeply investigated by Nuclear Magnetic Resonance (NMR). This compound represents an important step in the attempt to develop a novel strategy to interfere with the peculiar Trypanosoma Brucei redox system, making it possible to shed light on the perturbation of this biochemical machinery and eventually to novel therapeutic possibilities.
布氏锥虫是一种动基体目原生动物，可引起人类昏睡病和牛、马的那加那病。这种寄生虫的一个特点是其氧化还原代谢。参与这种氧化还原机制的蛋白质之一是单硫醇谷胱甘肽还原酶 1（1CGrx1），其特征是在锥虫和其他生物体中特有的独特无序 N 端延伸。该区域调节谷胱甘肽/ 三磷酸鸟苷结合位点的结合谱，这是 1CGrx1 的功能区域之一。没有内源性配体与该蛋白结合，因为它没有形成良好的结合位点，这使得该蛋白成为一个特别具有挑战性的靶向目标。为了针对这个特殊的系统，我们进行了两次不同的筛选：（i）针对 1CGrx1 的 N 端和典型结合位点的基于片段的先导化合物发现；（ii）针对 1CGrx1 典型结合位点的基于结构的虚拟筛选。在这里，我们报告了一种小分子，它结合在谷胱甘肽结合位点上，通过核磁共振（NMR）深入研究了该分子的结合模式。该化合物代表了试图开发一种新策略来干扰独特的布氏锥虫氧化还原系统的重要一步，这使得有可能阐明这种生化机制的干扰，并最终产生新的治疗可能性。
