Solids NMR Characterization of Bacterial Cell Walls

该项目旨在继续开发固体核磁共振作为表征细菌肽聚糖的工具，特别是枯草杆菌的肽聚糖。在含有13C和15N标记氨基酸的特定培养基中生长的细菌的整个细胞和细胞壁都将通过固体核磁共振进行检查，以鉴定和定量分析细胞壁亚结构。将开发气相色谱-质谱学技术来补充核磁共振数据，并将允许在存在标记扰乱的情况下进行完整分析。细菌细胞壁对这些生物在环境中的存在至关重要，其新陈代谢是抗生素攻击的主要焦点。最近对绿色弧菌进行了核磁共振实验，旨在开发一种新的测定细胞壁交联度的分析技术。这种细菌可以很容易地运输标记的丙氨酸和赖氨酸，并将它们整合到细胞壁中，而不会发生混乱。然后，核磁共振可以用来直接测量细菌细胞壁的交联物密度。固体核磁共振作为表征细菌细胞壁肽聚糖亚基结构的工具的发展中的一个重要步骤是将该技术扩展到更常被研究的细菌，例如枯草杆菌。

This project is designed to continue the development of solids state NMR as a tool for characterization of bacterial peptidoglycan, specifically the peptidoglycan of B. subtilis. Both whole cells and cell walls of bacteria grown in defined media containing 13C and 15N -labeled amino acids will be examined by solids state NMR for the identification and quantitative analysis of cell wall substructures. Gas chromatograph-mass spectroscopy techniques will be developed to complement the NMR data and will allow complete analyses in the presence of label scrambling. The bacterial cell wall is vital for the existence of these organisms in the environment and its metabolism represents a major focus for attack by antibiotics. Recent NMR experiments aimed at developing a new analytical technique for determination of cell-wall cross-linking were carried out on the bacterium A. viridans. This bacterium transports both labeled alanine and lysine readily and incorporates them into the cell wall with no scrambling. NMR can then be used to measure directly the cross-link density in the bacterial cell wall. An important step in the development of solids state NMR as a tool for the characterization of peptidoglycan substructures in bacterial cell walls is an extension of the technique to bacteria which are more commonly studied, e.g. B. Subtilis.***//