Designer ?1,6-Fucosidase Mutants Enable Direct Core Fucosylation of Intact N-Glycopeptides and N-Glycoproteins.
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ABSTRACT: Core fucosylation of N-glycoproteins plays a crucial role in modulating the biological functions of glycoproteins. Yet, the synthesis of structurally well-defined, core-fucosylated glycoproteins remains a challenging task due to the complexity in multistep chemical synthesis or the inability of the biosynthetic ?1,6-fucosyltransferase (FUT8) to directly fucosylate full-size mature N-glycans in a chemoenzymatic approach. We report in this paper the design and generation of potential ?1,6-fucosynthase and fucoligase for direct core fucosylation of intact N-glycoproteins. We found that mutation at the nucleophilic residue (D200) did not provide a typical glycosynthase from this bacterial enzyme, but several mutants with mutation at the general acid/base residue E274 of the Lactobacillus casei ?1,6-fucosidase, including E274A, E274S, and E274G, acted as efficient glycoligases that could fucosylate a wide variety of complex N-glycopeptides and intact glycoproteins by using ?-fucosyl fluoride as a simple donor substrate. Studies on the substrate specificity revealed that the ?1,6-fucosidase mutants could introduce an ?1,6-fucose moiety specifically at the Asn-linked GlcNAc moiety not only to GlcNAc-peptide but also to high-mannose and complex-type N-glycans in the context of N-glycopeptides, N-glycoproteins, and intact antibodies. This discovery opens a new avenue to a wide variety of homogeneous, core-fucosylated N-glycopeptides and N-glycoproteins that are hitherto difficult to obtain for structural and functional studies.
SUBMITTER: Li C
PROVIDER: S-EPMC5695864 | biostudies-literature | 2017 Oct
REPOSITORIES: biostudies-literature
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