Technical University of Munich, TUM School of Natural Sciences, Department of Bioscience, Center for Functional Protein Assemblies (CPA), Ernst-Otto-Fischer Strasse 8, 85748, Garching bei München, Germany.
Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615N. Wolfe Street, E5132, MD 21205, Baltimore, USA.
Angew Chem Int Ed Engl. 2023 Aug 1;62(31):e202304533. doi: 10.1002/anie.202304533. Epub 2023 Jun 26.
The development of novel anti-infectives requires unprecedented strategies targeting pathways which are solely present in pathogens but absent in humans. Following this principle, we developed inhibitors of lipoic acid (LA) salvage, a crucial pathway for the survival of LA auxotrophic bacteria and parasites but non-essential in human cells. An LA-based probe was selectively transferred onto substrate proteins via lipoate protein ligase (LPL) in intact cells, and their binding sites were determined by mass spectrometry. Probe labeling served as a proxy of LPL activity, enabling in situ screenings for cell-permeable LPL inhibitors. Profiling a focused compound library revealed two substrate analogs (LAMe and C3) as inhibitors, which were further validated by binding studies and co-crystallography. Importantly, LAMe exhibited low toxicity in human cells and achieved killing of Plasmodium falciparum in erythrocytes with an EC value of 15 μM, making it the most effective LPL inhibitor reported to date.
新型抗感染药物的开发需要前所未有的策略，针对仅存在于病原体中而不存在于人体中的途径。基于这一原则，我们开发了硫辛酸（LA）补救途径的抑制剂，该途径对于 LA 营养缺陷型细菌和寄生虫的存活至关重要，但在人体细胞中是非必需的。基于 LA 的探针通过脂酰基辅酶 A 连接酶（LPL）在完整细胞中选择性地转移到基质蛋白上，并通过质谱确定其结合位点。探针标记可作为 LPL 活性的替代物，从而能够在原位筛选细胞通透的 LPL 抑制剂。对靶向化合物文库的分析揭示了两种底物类似物（LAMe 和 C3）作为抑制剂，通过结合研究和共结晶进一步验证。重要的是，LAMe 在人细胞中毒性低，并以 EC 值为 15 μM 的浓度在红细胞中实现了对疟原虫的杀伤，使其成为迄今为止报道的最有效的 LPL 抑制剂。
