NGT介导的非wzy依赖途径细菌多糖蛋白质缀合物疫苗生产

化学法生产多糖蛋白缀合物疫苗具有诸多不足。生物法可避免现有缺点。细菌表面多糖的合成机制有三种：wzy依赖，ABC转运器依赖和合酶依赖途径。目前利用PglB/PglL解决了wzy依赖细菌多糖蛋白缀合物的生物合成难题。其余两种非wzy依赖多糖蛋白缀合物的生物法合成仍有待解决。基于两种非wzy依赖细菌表面多糖合成过程与NGT介导蛋白质N-糖基化途径的相似性，我们设想将这两种非wzy依赖细菌多糖合成过程与NGT介导的蛋白糖基化过程偶联，用来合成非wzy依赖多糖蛋白缀合物疫苗。我们拟选用肺炎链球菌3型作为合酶依赖模式菌，E.coli O8作为ABC转运器依赖模式菌。在了解NGT酶学性质基础上，建立识别不同糖核苷酸的NGT酶库，进而建立一种新的多糖蛋白缀合疫苗生物合成方法。本项目不仅解决了非wzy依赖细菌多糖蛋白缀合物疫苗生物法合成难题，而且扩大了酶法合成糖蛋白缀合疫苗的应用范围。

Glycoconjugate vaccine provides an attractive approach for fighting the infectious diseases. The traditional approach suffers from multiple fermentations, purification steps, low yields, and therefore, leading to the high cost of vaccine production. The objective of this proposal is to explore bacterial protein glycosylation systems to obtain polysaccharide conjugate vaccines in an efficient, and easily applicable way.There are three mechanisms of bacteria polysaccharides synthesis: wzy dependent pathway, ABC transporter dependent pathway and synthase-dependent pathway. The production of glycoconjugates of non-wzy dependent pathways remains to be resolved. Based on the similarity of non-wzy-dependent pathway and bacteria protein N-glycosylation pathways, these two pathways were coupled to synthesize non-wzy-dependent polysaccharide protein conjugate vaccines. NGT is used to produce bacterial glycoconjugates of non-wzy- dependent pathways.