Biochemistry of pathogenic bacteria: Isobacteriochlorin heme d1 biosynthesis in Pseudomonas aeruginosa

病原菌的生物化学：铜绿假单胞菌中异细菌二氢血红素 d1 的生物合成

• 批准号: 58324522
• 负责人: Professorin Dr. Gunhild Monika Layer
• 金额: --
• 依托单位: Lehrstuhl für Pharmazeutische Biologie und Biotechnologie
• 依托单位国家: 德国
• 项目类别: Independent Junior Research Groups
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/58324522?language=en
• 关键词: Biochemistry; pathogenic; bacteria; Isobacteriochlorin; heme

Anaerobic growth and survival of Pseudomonas aeruginosa is essential for biofilm formation and infection. Replacement of the electron acceptor oxygen by nitrate during anaerobic denitrification (NO3-  NO2-  NO  N2O  N2) is a powerful strategy for anaerobic energy generation and ecologically indispensable for the global nitrogen cycle. In the second step of the denitrification process the dissimilatory nitrite reductase (cytochrome cd1) utilizes the prosthetic groups heme c and heme d1 for the reduction of NO2- to NO. Heme d1 is not a real heme, rather an isobacteriochlorin related to siroheme, vitamin B12 and coenzyme F430. The multistep biosynthesis of this unique cofactor is only poorly understood. This proposal focuses on the investigation of the biosynthetic raute leading to the formation of heme d1 in P. aeruginosa. The main objectives are the identification of biosynthetic intermediates and the elucidation of the catalytic properties of involved enzymes. For the stepwise identification of involved metabolites and enzymes available mutants of the involved nirCFDLGHJEN genes will be physiologically, genetically and biochemically characterized. Selected recombinant Nir proteins will be subjected to thorough biochemical and biophysical characterization to deduce their catalytic properties. Since heme d1 biosynthesis reconstitutes a unique bacterial target the impact of genetic pathway disruption on biofilm formation and infection are of general medical interest.

铜绿假单胞菌的厌氧生长和存活对生物膜的形成和感染是必不可少的。在厌氧反硝化过程中用硝酸盐代替电子受体氧(NO3-NO2-noN2ON2)是一种强有力的厌氧能源产生策略，在全球氮循环中生态上是不可或缺的。在反硝化过程的第二步，异化亚硝酸还原酶(细胞色素CD1)利用辅基血红素c和血红素d1将NO2-还原为NO。亚铁血红素D1不是真正的亚铁血红素，而是一种与亚铁血红素、维生素B12和辅酶F430相关的同细菌碘氯。这种独特的辅因子的多步骤生物合成还知之甚少。这项建议侧重于研究导致铜绿假单胞菌中血红素D1形成的生物合成Raute。主要目标是鉴定生物合成中间体和阐明所涉及的酶的催化性质。为了逐步鉴定相关的代谢物和可用的酶，将对涉及的nirCFDLGHJEN基因的突变体进行生理、遗传和生化特征的鉴定。选定的重组NIR蛋白将经过彻底的生化和生物物理表征，以推断其催化性质。由于血红素D1的生物合成重建了一个独特的细菌靶标，因此遗传途径中断对生物膜形成和感染的影响引起了广泛的医学兴趣。