CAREER: Chemical Tools for Understanding the Mycomembrane of the Corynebacterineae

通过这一奖项，化学部的生命过程化学计划资助中密歇根大学的Benjamin Swarts博士研究存在于棒状杆菌亚目数百种细菌中的一种独特细胞膜的结构和动力学。所有细菌都有带有一层或两层膜的细胞膜，这些膜在细胞防御、通讯和结构完整性方面发挥着关键作用。棒状杆菌中的物种有两层膜，最外层主要由称为霉菌酸结合物的复杂糖链脂类组成。这种“菌膜”是棒状杆菌所特有的，并赋予它们独特的生理和致病特性。由于在使用标准实验技术时遇到的挑战，菌膜的生产、维护和组成的许多方面仍然未知。这个项目产生并利用新的化学生物学工具来表征真菌膜的结构和动力学。正在开发的工具是更好地了解棒状杆菌如何在其内部生存并适应其周围环境的过程的重要组成部分。此外，对这种细菌系统的调查有助于了解细菌与环境相互作用的性质，并提供信息，以加强对病原体的环境控制。从事这项研究的本科生和博士后研究员获得了有机合成、微生物学和蛋白质组学方面的跨学科培训。这项研究还被纳入一个外展计划，向社区大学生介绍化学细菌学研究，并鼓励他们继续进行科学教育。在这个项目中产生的工具有望具有广泛的实用价值，并支持其他科学家从事棒状杆菌的基础和应用研究。传统的生化和分子生物学方法不太适合研究菌膜，因为它主要由非遗传编码的脂类和糖组成。这项研究项目开发了利用天然代谢途径将标签引入完整细菌细胞的特定菌膜成分的化学探针。然后，根据实验的目标，标记的分子通过质谱学进行成像或识别。本项目中开发的探针提供了以下信息：(I)当细菌受到压力时，菌膜的主要糖脂成分是如何合成和重塑的；以及(Ii)哪些蛋白质驻留在菌膜中并对菌膜的构建和维护做出贡献。该项目的发现将有助于更好地了解菌膜结构和动力学，并为棒状杆菌亚目细菌的生理学提供洞察力。

With this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Dr. Benjamin Swarts at Central Michigan University to investigate the structure and dynamics of a unique cell membrane present in hundreds of bacterial species of the suborder Corynebacterineae. All bacteria have cell envelopes with one or two membranes that play critical roles in cellular defense, communication, and structural integrity. Species in the Corynebacterineae have two membranes, the outermost of which is composed mostly of complex sugar-linked lipids called mycolic acid conjugates. This "mycomembrane" is unique to the Corynebacterineae and gives them distinctive physiological and pathogenic characteristics. Many aspects of the production, maintenance, and composition of the mycomembrane remain unknown because of the challenges encountered when using standard experimental techniques. This project generates and utilizes new chemical biology tools to characterize the structure and dynamics of the mycomembrane. The tools being developed form a significant part of the process of acquiring a better understanding of how the Corynebacterineae survive within and adapt to their surrounding environment. In addition, an investigation of this bacterial system advances understanding of the nature of interactions of bacteria with the environment and provides information that would enhance efforts to gain environmental control of pathogens. Undergraduate students and postdoctoral fellows working on this research acquire interdisciplinary training in organic synthesis, microbiology and proteomics. This research is also integrated into an outreach program that introduces community college students to chemical bacteriology research and encourages their continued education in science. The tools generated in this project are expected to have broad utility and to support other scientists pursuing basic and applied research on the Corynebacterineae.Traditional biochemical and molecular biological approaches are not well-suited to investigating the mycomembrane because it is made up largely of non-genetically encoded lipids and sugars. This research project develops chemical probes that exploit native metabolic pathways to introduce tags into specific mycomembrane components in intact bacterial cells. Tagged molecules are then imaged or identified by mass spectrometry, depending on the goal of the experiment. The probes developed in this project provide information on (i) how the major glycolipid constituents of the mycomembrane are synthesized and remodeled when the bacterium encounters stress; and (ii) what proteins reside within and contribute to the construction and maintenance of the mycomembrane. The findings from this project will lead to an improved understanding of mycomembrane structure and dynamics and provide insight into the physiology of bacteria in the Corynebacterineae suborder.