Cell surface display of bacterial proteins

暴露在细菌细胞表面的蛋白质在细胞生长和分裂等许多基本过程中发挥着关键作用。在病原体中，表面蛋白促进宿主入侵，随后在感染期间逃避宿主免疫反应。大多数表面蛋白都固定在一种名为肽聚糖的支架分子上，这是细菌包膜的基本成分。肽聚糖是一种包裹在细胞周围的袋状巨大分子，对细胞起到保护作用。它的合成是细菌独有的，是迄今发现的最重要的抗生素(如青霉素)的靶标。到目前为止，已经描述了大量的表面蛋白，但它们如何与细菌包膜相互作用仍然知之甚少。最近，我们利用人工合成的配体，在体外描述了一个被称为LysM的无处不在的蛋白质结构域识别肽聚糖的分子基础。我们现在准备采取下一步，以实际了解LysM蛋白如何与活细菌中复杂的肽聚糖分子结合，并针对特定的亚细胞定位。为了实现这一目标，我们将使用结合细菌遗传学、最新显微镜和生物物理学的多学科方法。LysM结构域与PG分子的结合是控制细胞壁特征的定位、合成、降解和修饰的关键细菌机制。这个项目产生的理解将为我们提供工具来剖析细菌是如何生长、分裂和与环境相互作用的，开发新的治疗策略，并学习如何将合成生物学应用于细菌细胞壁。

The proteins exposed at the cell surface of bacteria play a pivotal role in a multitude of fundamental processes such as cell growth and division. In pathogens, surface proteins promote host invasion and later during infection, evasion from the host immune response. Most surface proteins are anchored to a scaffold molecule called peptidoglycan, an essential component of the bacterial envelope. Peptidoglycan is a bag-shaped giant molecule surrounding the cell that made plays a protective role. Its synthesis is unique to bacteria and represents the target of the most important antibiotics ever discovered such as penicillin. To date, a plethora of surface proteins has been described but how they interact with the bacterial envelope remain poorly understood. We have recently described the molecular basis for peptidoglycan recognition by a ubiquitous protein domain called LysM in vitro using synthetic ligands. We are now ready to take the next step to actually understand how LysM proteins bind to the complex peptidoglycan molecule in live bacteria and are targeted to specific subcellular localizations. To achieve this aim, we will use a multidisciplinary approach combining bacterial genetics, state-of-the-art microscopy and biophysics. Binding of LysM domains to the PG molecule represents a key bacterial mechanism for controlling the location, synthesis, degradation and decoration of cell wall features. The understanding generated by this project will give us the tools to dissect how bacteria grow, divide and interact with their environment, to develop new therapeutic strategies, and to learn how to apply synthetic biology to bacterial cell walls.