Discovery and characterization of bioactive phosphonic acid biosynthetic pathways

膦酸具有稳定的碳磷键。人们已经发现了许多天然产生的具有抗菌活性的膦酸盐。淡黄色链霉菌产生的磷酸盐磷霉素在早期抑制类异戊二烯生物合成的非甲戊酸途径，阻断脱氧果糖磷酸还原异构酶(DXR)。在引起恶性疟原虫的疟疾中已经检测到这一途径，并且已经证明磷霉素对这种寄生虫是有效的。本项目的目的是研究磷霉素的生物合成途径，并阐明对该化合物产生抗性的分子基础。该次生代谢物的生物合成基因簇已被克隆和测序。已鉴定的开放阅读框表明，磷霉素途径不同于最近阐明的结构相似的化合物FR900098的途径。将产生基因敲除突变体，并分析它们的生产情况。此外，将在体外测试酶反应，以证明所提出的途径，并了解作用于C-P化合物的酶的生物化学。该途径的阐明将有助于通过组合生物合成开发新型的膦酸类先导化合物。

Phosphonic acids are characterized by stable carbon-phosphorus bonds. A number of naturally produced phosphonates have been discovered which possess antibiotic activity. Fosmidomycin, a phosphonate produced by Streptomyces lavendulae, inhibits the nonmevalonate pathway of isoprenoid biosynthesis at an early stage, blocking the enzyme deoxyxylulose phosphate reductoisomerase (DXR). This pathway has been detected in the Malaria causing parasite Plasmodium falciparum, and fosmidomycin has been demonstrated to be active against this parasite. The aim of this project is to investigate the biosynthetic pathway of fosmidomycin and to elucidate the molecular basis of resistance against this compound. The biosynthetic gene cluster of this secondary metabolite has been cloned and sequenced. The identified open reading frames suggest that the fosmidomycin pathway differs from the recently elucidated pathway of the structurally similar compound FR900098. Knock-out mutants will be generated and analyzed for their production profile. Furthermore, enzymatic reactions will be tested in vitro to prove the proposed pathway and to understand the biochemistry of enzymes acting on C-P compounds. The elucidation of the pathway will help develop novel phosphonate lead compounds via combinatorial biosynthesis.