Analysis Of Ginkgo Seed Glycoprotein N-glycans And Its Allergenicity

Ginkgo biloba L.is a homologous plant of Medicine and Edible with anti-oxidation,antifatigue and anti-aging effects.However,ginkgo seed has allergenicity and their glycoprotein is potential allergen.Studies have shown that allergic reactions are caused by the specific binding of glycoprotein N-glycans and IgE antibodies in vivo,and the binding sites may be related to the N-glycan types,but currently ginkgo seed glycoprotein glycans are few studies.Therefore,studying the N-glycans from ginkgo seed and their effects on sensitization in mice is of great significance for further understanding the ginkgo seed sensitization mechanism.In this experiment,the ginkgo seed protein was used as the research material,and the glycoprotein glycan structure,the main glycoprotein antigenic determinant and its sensitization were analyzed,which laid a foundation for studying the biological function of ginkgo seed glycoprotein glycan.The main results as follows: 1.The sugar content and protein content of ginkgo seed protein were determined by phenol sulfuric acid method and Braford method.The results showed that the sugar content of ginkgo seed protein was about 11.6% and the protein content about 54.5%.2.The N-glycans released from ginkgo seed protein and separation protein gels were qualitatively and quantitatively via ESI-MS and online LC-UV-MS/MS2.The results showed that 11 N-glycans containing oligomannose type N-glycans(4.88%)and complex type N-glycans(95.12%)were obteined in the ginkgo seed protein.In addition,the obtained 11 proteins all were glycoproteins by SDS-PAGE gel electrophoresis,and the most Nglycans were modified by the core ?-1,3-fucose and ?-1,2-xylose in the 21000,36000 and 50000 Da glycoproteins,which accounted for 68.23%,64.37% and 75.09% respectively.3.Bioinformatics technology was used to predict the main ginkgo seeds glycoprotein Ginnacin B cell epitope.The results showed that six B cell epitopes were predicted,namely peptide1-6: NAQEP,GCPETFQSSTSRGGEGQQSQE,TSNDQNQ,PGPPSDDYERER,RAGQNPNRPKRR,PTPQHQQPR.4.The established Balb/c mice were used as sensitization models,and the sensitization of ginkgo seed protein and de-glycosylated protein was evaluated.Compared with the de-glycoprotein group,the glycoprotein group body weight increased rapidly,the rectal temperature changed greatly,the histamine and IgE levels increased significantly.Observation of histopathological sections revealed that the glycoprotein group had a greater degree of tissue damage,indicating that the N-glycan may have an enhancing effect in ginkgo protein sensitization.