GLYCOPEPTIDE COMPLEXES WITH BACTERIAL CELL WALLS BY REDOR

 描述（由申请方提供）：估计50-70%的导管相关感染、40-50%的人工心脏瓣膜感染和20-50%的关节置换感染是由葡萄球菌生物膜引起的，其中金黄色葡萄球菌是主要病原体。生物膜研究中目前的挑战是难以确定生物膜的确切性质（组成），并且生物膜组成从一种生物体到另一种生物体变化很大。非均相生物膜的表征不适合于常规的光谱方法。在下一个资助期内，我们计划研究S.金黄色葡萄球菌使用组合的固态NMR和液相色谱/质谱法，以确定生物膜组成和局部结构，并建立可以灭菌成熟生物膜的药物的作用模式。我们将深入了解复杂生物膜的局部结构和功能， 使用一系列特定的稳定同位素标记。这种固态NMR方法用于生物膜原位分析的发展是在分子水平上评估靶向生物膜的新型化学和生物制剂的新平台，因此有望用于治疗和预防生物膜相关感染。我们的具体目标是：（i）确定由野生型和突变株形成的成熟生物膜的组成和结构组织。金黄色。(ii)确定奥利万星杀灭S.金黄色葡萄球菌细胞在静止相条件下。(iii)确定新型抗生物膜剂对S.金黄色。糖肽奥利万星（2014年9月被FDA批准用于临床）已被证明可以杀死静止期生物膜S。金黄色葡萄球菌，最小生物膜根除浓度仅为2-4 µg/mL。没有其他已知的糖肽抗生素具有这种杀菌能力。我们打算专注于了解奥利万星对成熟生物膜的破坏，第二个目标是解开其对生物膜形成的抑制作用。我们对生物膜抑制和杀菌的了解应该适用于第二代奥利万星样糖肽类杀菌剂的设计。

 DESCRIPTION (provided by applicant): An estimated 50-70% of catheter-related infections, 40-50% prosthetic cardiac-valve infections, and 20-50% of joint-replacement infections are caused by staphylococci biofilms, of which Staphylococcus aureus is the leading pathogen. The current challenges in biofilm studies are that the exact nature (composition) of the biofilm is difficult to determine, and the biofilm composition varies greatly from one organism to another. The characterization of heterogeneous biofilms is not amenable to conventional spectroscopic methods. In the next grant period, we propose to examine biofilms of S. aureus using combined solid-state NMR and liquid-chromatography/mass-spectrometry, to determine biofilm composition and local structure, and to establish the mode of action of drugs that can sterilize mature biofilms. We will gain insights into local structure and function in complicated biofilms by using a collection of specific stable-isotope labels. This development of solid-state NMR methods for in situ analyses of biofilms is a new platform for evaluating at the molecular level novel chemical and biological agents that target biofilms and hence holds promise for the treatment and prevention of biofilm-related infections. Our specific aims are: (i) Determine the composition and structural organization of mature biofilms formed by wild-type and mutant strains of S. aureus. (ii) Determine the mode of action of oritavancin in killing S. aureus cells under stationary-phase conditions. (iii) Determine the mode of action of novel anti-biofilm agents for S. aureus. The glycopeptide, oritavancin (which was approved for use in the clinic by the FDA in September, 2014) has been shown to kill stationary-phase biofilm S. aureus with a minimal biofilm eradication concentration of only 2-4 µg/mL. No other known glycopeptide antibiotic has this sterilizing capability. We intend to focus on understanding the destruction of mature biofilms by oritavancin, with a secondary goal of unraveling its inhibition of biofilm formation. What we learn about biofilm inhibition and sterilization should be applicable to the design of second-generation oritavancin-like glycopeptide bactericides.