Discovery and characterization of bioactive phosphonic acid biosynthetic pathways

膦酸具有稳定的碳磷键。许多自然产生的磷酸盐已被发现具有抗生素活性。Fosmidomycin是一种由薰衣草链霉菌（Streptomyces laendulae）产生的膦酸盐，在早期抑制类异戊二烯生物合成的非甲羟酸途径，阻断脱氧纤维素磷酸还原异构酶（DXR）。这一途径已在引起疟疾的疟原虫恶性疟原虫中被发现，并已证明磷霉素对这种寄生虫有活性。本课题旨在探讨磷霉素的生物合成途径，并阐明其耐药的分子基础。该次生代谢物的生物合成基因簇已被克隆并测序。发现的开放阅读框表明fosmidomycin通路不同于最近发现的结构相似的化合物FR900098的通路。敲除突变体将生成并分析其生产概况。此外，酶促反应将在体外进行测试，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膦酸铅化合物。

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.