The methylerythritol phosphate pathway is functionally active in all intraerythrocytic stages of Plasmodium falciparum
The methylerythritol phosphate pathway is functionally active in all intraerythrocytic stages of Plasmodium falciparum
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DOI：
10.1074/jbc.m408360200
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发表时间：
2004-12-10
影响因子：
4.8
通讯作者：
Katzin, AM
中科院分区：
文献类型：
--
作者：
Cassera, MB;Gozzo, FC;Katzin, AM
最近发现了两个编码1-脱氧-D-木酮糖-5-磷酸合成酶和1-脱氧-D-木酮糖-5-磷酸还原异构酶的基因，表明恶性疟原虫中类异戊二烯的生物合成依赖于甲基异戊烯磷酸（MEP）途径，并且磷咪霉素可以抑制1-脱氧-D-木酮糖-5-磷酸还原异构酶的活性。代谢物1-脱氧-D-木酮糖-5-磷酸不仅是异戊烯基二磷酸生物合成的MEP途径的中间体，而且还参与植物和许多微生物中硫胺素（维生素B-1）和吡哆醛（维生素B-6）的生物合成。在这里，我们报告的第一个分离和鉴定的MEP途径的最下游中间体的三个红细胞内阶段的恶性疟原虫。这些包括1-脱氧-D-木酮糖-5-磷酸、2-C-甲基-D-β-4-磷酸、4-（胞苷-5-二磷酸）-2-C-甲基-D-β-2-磷酸、4-（胞苷-5-二磷酸）-2-C-甲基-D-β-2-磷酸和2-C-甲基-D-β-2，4-环二磷酸。通过HPLC纯化这些中间体，并通过生物化学和电喷雾质谱分析进行结构表征。我们还研究了磷咪霉素对该途径的每个中间体的生物合成和类异戊二烯生物合成（长萜和泛醌）的影响。因此，首次证明MEP途径在所有红细胞内形式的恶性疟原虫中具有功能活性，并报道了原生动物中吡哆醛的从头生物合成。它在人类宿主中的缺失使得这两种途径作为抗疟药物开发的潜在新靶点非常有吸引力。
Two genes encoding the enzymes 1-deoxy-D-xylulose-5-phosphate synthase and 1-deoxy-D-xylulose-5-phosphate reductoisomerase have been recently identified, suggesting that isoprenoid biosynthesis in Plasmodium falciparum depends on the methylerythritol phosphate ( MEP) pathway, and that fosmidomycin could inhibit the activity of 1-deoxy-D-xylulose-5-phosphate reductoisomerase. The metabolite 1-deoxy-D-xylulose-5-phosphate is not only an intermediate of the MEP pathway for the biosynthesis of isopentenyl diphosphate but is also involved in the biosynthesis of thiamin (vitamin B-1) and pyridoxal (vitamin B-6) in plants and many microorganisms. Herein we report the first isolation and characterization of most downstream intermediates of the MEP pathway in the three intraerythrocytic stages of P. falciparum. These include, 1-deoxy-D-xylulose-5-phosphate, 2-C-methyl-D-erythritol-4-phosphate, 4-(cytidine-5-diphospho)-2-C-methyl-D-erythritol, 4-(cytidine-5-diphospho)-2-C-methyl-D-erythritol-2-phosphate, and 2-C-methyl-D-erythritol-2,4-cyclodiphosphate. These intermediates were purified by HPLC and structurally characterized via biochemical and electrospray mass spectrometric analyses. We have also investigated the effect of fosmidomycin on the biosynthesis of each intermediate of this pathway and isoprenoid biosynthesis (dolichols and ubiquinones). For the first time, therefore, it is demonstrated that the MEP pathway is functionally active in all intraerythrocytic forms of P. falciparum, and de novo biosynthesis of pyridoxal in a protozoan is reported. Its absence in the human host makes both pathways very attractive as potential new targets for antimalarial drug development.