Developing glycan-directed tools to investigate microbial infection

7.项目总结/摘要 覆盖在细菌表面的聚糖和糖缀合物强调了在各种生物学过程中的关键作用。 流程.一个这样的过程，目前缺乏机械知识，是N-连接的相互作用， 来自肠道病原体空肠弯曲杆菌的七糖与宿主细胞受体，导致人 感染其他病原菌中的N-和O-糖基化系统也显示出类似的基本相互作用 以保持毒性。因此，了解这些聚糖-受体相互作用将提供以下信息 微生物感染背后的分子机制，并揭示未来治疗干预的见解。 目前的生物化学工具缺乏研究宿主-病原体相互作用的适当特征， 由此产生的对开发聚糖导向工具的需求，这些工具可以用来阐明关键的 发病机制的分子决定因素。拟议的项目侧重于产生独特的生化 物种，以了解N-糖基化在C.空肠感染具体而言，这些包括聚糖- 修饰的磁珠、多价聚糖官能化肽和聚糖特异性蛋白质结合剂。的 两种多价聚糖支架将通过生物缀合物化学和化学酶化学获得。 合成和所得的化学限定的支架可以通过酵母提供特定的蛋白质结合剂 表面显示定向进化。所有三个物种将应用于微生理胃肠道模型 （GutChip）的C.空肠感染提供致病机制信息。 聚糖包被的磁珠与宿主细胞受体相互作用，允许阐明特定蛋白质 其结合聚糖。七糖片段的多价聚糖官能化聚合物可以竞争 宿主细胞受体，提供关于C.空肠聚糖区参与发病机制。演进 蛋白质结合剂可以掩盖暴露的N-聚糖，阻碍聚糖介导的感染机制。的 从C.空肠模型将广泛适用于其他细菌威胁，因此 对糖和微生物学社区来说是无价的。 该项目将在Barbara Imperiali教授的赞助下进行， 在马萨诸塞州理工学院的生物和化学。她的支持，实验室的专业知识， 麻省理工学院丰富的资源将使拟议的研究项目得以成功完成。

7. Project Summary/Abstract Glycans and glycoconjugates coating the surface of bacteria underscore critical roles in various biological processes. One such process, which currently lacks mechanistic knowledge, is the interaction of the N-linked heptasaccharide from enteric pathogen Campylobacter jejuni with host cell receptors, resulting in human infection. N- and O-glycosylation systems in other pathogenic bacteria have shown similar essential interactions to maintain virulence. Therefore, understanding these glycan-receptor interactions will provide information on the molecular mechanisms behind microbial infection and reveal insights for future therapeutic intervention. Current biochemical tools lack appropriate characteristics to study host-pathogen interactions, and there is a resulting demand for the development of glycan-directed tools which can be leveraged to elucidate critical molecular determinants of pathogenesis. The proposed project focuses on the generation of unique biochemical species to understand the role of N-glycosylation in C. jejuni infection. Specifically, these include glycan- decorated magnetic beads, multivalent glycan-functionalized peptides and glycan-specific protein binders. The two multivalent glycan scaffolds will be attained through bioconjugate chemistries and chemoenzymatic synthesis and the resulting chemically-defined scaffolds can afford specific protein binders through a yeast surface display directed evolution. All three species will be applied in a microphysiological gastrointestinal model (GutChip) of C. jejuni infection to afford pathogenic mechanistic information. Glycan-coated magnetic beads interact with host cell receptors, allowing for the elucidation of the specific protein which binds glycans. Multivalent glycan-functionalized polymers of heptasaccharide fragments can compete for host cell receptors, providing information on the C. jejuni glycan regions involved in pathogenesis. The evolved protein binders may mask the exposed N-glycan, thwarting glycan-mediated infectious mechanisms. The lessons learned from the C. jejuni model will be broadly-applicable to other bacterial threats and therefore invaluable to the glyco- and microbiology communities. This project will be performed under the sponsorship of Professor Barbara Imperiali, in the Departments of Biology and Chemistry at Massachusetts Institute of Technologies. Her support, the lab’s expertise, and the wealth of resources available at MIT will allow for the successful completion of the proposed research project.