Study On N-glycosylational Modification Of Human IgG1-Fc Expressed In Insect And Baculovirus System

Insect and baculovirus expression system can proceed with N-glycosylational modification of expressed recombinant glycoproteins,and has the potential prospect that this system can express N-glycosylational modificated functional proteins from the mammalian. It has the processing capacity of co-translation,including the glycosylation,the phosphorylation,the excision of signal peptide,the cutting and decomposition polypeptide,and its modified sites are the same as ones of natural proteins in cells. Comparative experiments proved that the glycosylated sites in insect and mammalian cells were in full agreement,but the modified oligosaccharide's species were not very consistent. The influence that this inconsistent has on different target protein is different,so insects expression system can be considered as a ideal model that study on the glycosylation's impact on protein's structure and functions.Human IgG1 is the important immunoglobulins in vivo,and its immune function is related closely with N-glycosylational modification.This paper was aimed to exprss Fc fragment of human IgG1 where N-glycosylational modification happen.Experimental results showed that the expressed level of human IgG1-Fc protein was very high.After purificated by Protein A column,human IgG1-Fc was dealed with by glycosidase enzyme PNGase F,the result showed that N-glycosylational modification of human IgG1-Fc happened in N297 glycosylational site. This research is to lay a solid foundation for two aspects that one is the glycosylational echanism in insect cells,the other is that glycoproteins with medical value are expressed by transforming insect and baculovirus expression system.