Engineered Oligosaccharyltransferases With Unique N-Glycosylation Site Preferences
The key enzyme in the Campylobacter jejuni glycosylation pathway, PglB, has been one of the well-studied asparagine-linked oligosaccharyltransferase (OST) in bacterial glycoengineering area. While C. jejuni PglB performs well in transferring different glycans, the acceptor sites it can recognize are limited. We provided a thorough investigation into Desulfovibrio desulfuricans PglB (DdPglB), an OST sharing homology with C. jejuni PglB but having more relaxed sequon specificity. The sequon logo of DdPglB against XXNXT library were built through a high-throughput assay. Two engineered OSTs combining distinct transmembrane domain and periplasmic domain of PglBs from C. jejuni and D. desulfuricans was also investigated. And the study interestingly revealed they can lose all their glycosylation activities after the combination. According to the sequon logo we built and further verification, a notable sequon QYNST, which is a native acceptor sequon of Fc domain of human immunoglobulin G, was able to be glycosylated by DdPglB. Overall, we presented a series of sequons that can be glycosylated by DdPglB and further expanded the glycoengineering toolbox with more potential acceptor sites that were not glycosylated before.
Chemical engineering; Campylobacter jejuni; Desulfovibrio desulfuricans; Glycosylation; Oligosaccharyltransferases; PglB; sequon logo; Biomedical engineering
Daniel, Susan; Paszek, Matthew J.
M.S., Chemical Engineering
Master of Science
dissertation or thesis