Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan; Department of Parasitology, National Institute of Infectious Diseases (NIID), Tokyo, Japan; Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Japan; Research Center for Biology, Indonesia Institute of Sciences (LIPI), Cibinong, Indonesia.
Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Japan.
Int J Parasitol Drugs Drug Resist. 2018 Apr;8(1):125-136. doi: 10.1016/j.ijpddr.2018.02.004. Epub 2018 Mar 1.
The Coenzyme A (CoA), as a cofactor involved in >100 metabolic reactions, is essential to the basic biochemistry of life. Here, we investigated the CoA biosynthetic pathway of Entamoeba histolytica (E. histolytica), an enteric protozoan parasite responsible for human amebiasis. We identified four key enzymes involved in the CoA pathway: pantothenate kinase (PanK, EC 2.7.1.33), bifunctional phosphopantothenate-cysteine ligase/decarboxylase (PPCS-PPCDC), phosphopantetheine adenylyltransferase (PPAT) and dephospho-CoA kinase (DPCK). Cytosolic enzyme PanK, was selected for further biochemical, genetic, and phylogenetic characterization. Since E. histolytica PanK (EhPanK) is physiologically important and sufficiently divergent from its human orthologs, this enzyme represents an attractive target for the development of novel anti-amebic chemotherapies. Epigenetic gene silencing of PanK resulted in a significant reduction of PanK activity, intracellular CoA concentrations, and growth retardation in vitro, reinforcing the importance of this gene in E. histolytica. Furthermore, we screened the Kitasato Natural Products Library for inhibitors of recombinant EhPanK, and identified 14 such compounds. One compound demonstrated moderate inhibition of PanK activity and cell growth at a low concentration, as well as differential toxicity towards E. histolytica and human cells.
辅酶 A（CoA）作为参与>100 种代谢反应的辅助因子，对生命的基本生物化学至关重要。在这里，我们研究了参与肠原生动物寄生虫溶组织内阿米巴（E. histolytica）CoA 生物合成途径的关键酶，这种寄生虫是导致人类阿米巴病的原因。我们鉴定了 CoA 途径中的四种关键酶：泛酸激酶（PanK，EC 2.7.1.33）、双功能磷酸泛酰巯基乙胺基转移酶/脱羧酶（PPCS-PPCDC）、磷酸泛酰巯基乙胺基转移酶（PPAT）和去磷酸 CoA 激酶（DPCK）。细胞质酶 PanK 被选为进一步的生化、遗传和系统发育特征分析。由于溶组织内阿米巴 PanK（EhPanK）在生理上很重要，并且与人类同源物足够分化，因此该酶代表了开发新型抗阿米巴化学疗法的有吸引力的靶标。PanK 的表观遗传基因沉默导致 PanK 活性、细胞内 CoA 浓度和体外生长迟缓显著降低，这强化了该基因在溶组织内阿米巴中的重要性。此外，我们筛选了北里天然产物文库中重组 EhPanK 的抑制剂，并鉴定出 14 种此类化合物。一种化合物在低浓度下表现出对 PanK 活性和细胞生长的适度抑制作用，并且对溶组织内阿米巴和人类细胞具有差异毒性。
