Department of Chemistry and Biochemistry, University of Delaware, 140 Brown Lab, Newark, DE, 19716, USA.
Department of Biological Sciences, University of Delaware, 140 Brown Lab, Newark, DE, 19716, USA.
Chembiochem. 2019 Jun 3;20(11):1369-1375. doi: 10.1002/cbic.201800731. Epub 2019 Mar 21.
The innate immune system's interaction with bacterial cells plays a pivotal role in a variety of human diseases. Carbohydrate units derived from a component of bacterial cell wall, peptidoglycan (PG), are known to stimulate an immune response. Nonetheless, access to modified late-stage peptidoglycan intermediates is limited due to their synthetic complexity. A method to rapidly functionalize PG fragments is needed to better understand the natural host-PG interactions. Here methyl N,O-hydroxylamine linkers are incorporated onto a synthetic PG derivative, muramyl dipeptide (MDP). The modification of MDP maintained the ability to stimulate a nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) immune response dependent on the expression of nucleotide-binding oligomerization domain-containing protein 2 (Nod2). Intrigued by this modification's maintenance of biological activity, several applications were explored. Methyl N,O-hydroxylamine MDP was amendable to N-hydroxylsuccinimide (NHS) chemistry for bioconjugation to fluorophores as well as a self-assembled monolayer for Nod2 surface plasmon resonance analysis. Finally, linker incorporation was applicable to larger PG fragments, both enzymatically generated from Escherichia coli or chemically synthesized. This methodology provides rapid access to PG probes in one step and allows for the installation of a variety of chemical handles to advance the molecular understanding of PG and the innate immune system.
天然免疫系统与细菌细胞的相互作用在多种人类疾病中起着关键作用。已知细菌细胞壁成分肽聚糖 (PG) 的糖单位会刺激免疫反应。然而，由于其合成的复杂性，对经过修饰的晚期 PG 中间体的获取受到限制。需要一种快速对 PG 片段进行功能化的方法，以更好地了解天然宿主-PG 相互作用。在这里，甲基 N,O-羟胺接头被整合到合成 PG 衍生物，即 muramyl dipeptide (MDP) 上。MDP 的修饰保持了刺激核因子 kappa-轻链增强子的激活 B 细胞 (NF-κB) 免疫反应的能力，该反应依赖于核苷酸结合寡聚化结构域包含蛋白 2 (Nod2) 的表达。这种修饰保持生物活性的特性引起了人们的兴趣，探索了几种应用。甲基 N,O-羟胺 MDP 可适用于 N-羟基琥珀酰亚胺 (NHS) 化学，用于将荧光团进行生物偶联，以及用于 Nod2 表面等离子体共振分析的自组装单层。最后，接头的引入适用于更大的 PG 片段，这些片段可以通过大肠埃希菌酶促生成或化学合成获得。该方法在一步中提供了 PG 探针的快速获取，并允许安装各种化学处理，以推进对 PG 和天然免疫系统的分子理解。
