Exploring and Controlling Phenazine Biosynthesis with Chemical Biology

吩嗪类化合物是一类具有氧化还原活性的细菌次级代谢产物，它们通过充当抗生素和毒力因子而对细胞存活起重要作用。因此，它们的生物合成可能是治疗感染性疾病的新型药物的一个有趣的靶点。吩嗪通过涉及phzoperon中编码的酶的保守途径衍生自胆酸。尽管进展的过程中的一般理解，重要的细节仍然不清楚，由于吩嗪的生物合成过程中，通过几个不稳定的中间体，难以表征。特别地，申请人提出（1）研究2-氨基-2-脱氧异分支酸（ADIC）合酶PhzE和相关的邻氨基苯甲酸酯酶之间的差异，所述邻氨基苯甲酸酯酶将ADIC进一步转化为邻氨基苯甲酸酯，尽管具有非常相似的活性中心;（2）获得对PhzF的详细了解，其催化可能遵循周环反应机制的[1，5]-质子转移;（3）将PhzB的现有产物类似物开发成吩嗪生物合成的抑制剂，以及（4）了解PhzA/PhzB的生物化学相关性。PhzB在假单胞吩嗪生产者中的异二聚化。Blankenfeldt博士（MPI多特蒙德，德国）和Breinbauer教授（格拉兹科技大学，奥地利）的合作确保了这些目标将在三年的资助期内实现。合作伙伴在有机合成、生物化学和结构生物学方面拥有互补的专业知识，近年来，他们通过对吩嗪生物合成领域的重大贡献，展示了富有成效的合作。跨国融资将使两个博士学位。学生获得广泛的专业知识，在方法学上的异质性领域，拟议的研究将作出重大贡献，不仅通过提供新的酶机制的详细描述，但也工具化合物，可以作为铅结构对非那嗪生产微生物造成的传染病。

The phenazines are a large class of redox-active bacterial secondary metabolites that play an important role for cell survival by acting as antibiotics and virulence factors. Their biosynthesis may therefore be an interesting target for novel pharmaceuticals in the treatment of infectious disease. Phenazines derive from chorismic acid through a conserved pathway that involves enzymes encoded in the phzoperon. Despite progress in the general understanding of the process, important details are still unclear due to the fact that phenazine biosynthesis proceeds through several unstable intermediates that are difficult to characterize. This proposal aims at filling the existing gaps by combining synthetic chemistry with biochemical and structural techniques.In particular, the applicants propose to(1) investigate differences between 2-amino-2-desoxyisochorismate (ADIC) synthase PhzE and the related anthranilate synthases, which convert ADIC further to anthranilate despite having a very similar active center;(2) gain detailed insight into PhzF, which catalyzes a [1,5]-prototropic shift that may follow a pericyclic reaction mechanism;(3) develop existing product analogues of PhzB into inhibitors of phenazine biosynthesis and(4) understand the biochemical relevance of PhzA/PhzB heterodimerization in pseudomonal phenazine producers.The collaboration of Dr. Blankenfeldt (MPI Dortmund, Germany) and Prof. Dr. Breinbauer (Graz University of Technology, Austria) ensures that these aims will be met within the three years funding period. The partners possess complimentary expertises in organic synthesis, biochemistry and structural biology, and they have demonstrated a productive collaboration by contributing significantly to the field of phenazine biosynthesis in recent years. Transnational funding will enable two Ph.D. students to acquire a broad expertise in methodologically heterogeneous areas, and the proposed research will make significant contributions not only by providing detailed descriptions of novel enzyme mechanisms but also tool compounds that can be employed as lead structures against infectious disease inflicted by phenazine-producing microorganisms.