A bestatin-based chemical biology strategy reveals distinct roles for malaria M1- and M17-family aminopeptidases (3T8V, 3T8W)

Malaria causes worldwide morbidity and mortality, and while chemotherapy remains an excellent means of malaria control, drug-resistant parasites necessitate the discovery of new antimalarials. Peptidases are a promising class of drug targets and perform several important roles during the P. falciparum erythrocytic life cycle. Herein, we report a multidisciplinary effort combining activity-based protein profiling, biochemical, and peptidomic approaches to functionally analyze two genetically essential P. falciparum metallo-aminopeptidases (MAPs), PfA-M1 and Pf-LAP. Through the synthesis of a suite of activity-based probes (ABPs) based on the general MAP inhibitor scaffold, bestatin, we generated specific ABPs for these two enzymes. Specific inhibition of PfA-M1 caused swelling of the parasite digestive vacuole and prevented proteolysis of hemoglobin (Hb)-derived oligopeptides, likely starving the parasite resulting in death. In contrast, inhibition of Pf-LAP was lethal to parasites early in the lifecycle, prior to the onset of Hb degradation suggesting that Pf-LAP has an essential role outside of Hb digestion.

疟疾在全球范围内导致发病率和死亡率，尽管化疗仍然是疟疾控制的卓越手段，但耐药寄生虫的出现促使研究人员寻找新的抗疟药物。肽酶是一类具有潜力的药物靶点，并在恶性疟原虫的红细胞生命周期中扮演着多重重要角色。本研究报告了一个跨学科的研究努力，该研究结合了基于活性的蛋白质分析、生化分析和肽组学方法，以功能分析两种遗传上至关重要的恶性疟原虫金属肽酶（MAPs），即PfA-M1和Pf-LAP。通过合成一系列基于通用MAP抑制剂结构架的抑制肽（bestatin）的活性探针（ABPs），我们为这两种酶生成了特异性的ABPs。PfA-M1的特异性抑制导致寄生虫消化囊肿胀，并阻止了由血红蛋白（Hb）衍生而来的寡肽的蛋白水解，这可能导致寄生虫因饥饿而死亡。相反，Pf-LAP的抑制在生命周期早期对寄生虫具有致命性，在血红蛋白降解之前，这表明Pf-LAP在血红蛋白消化之外也起着至关重要的作用。