A Redox‐Controlled Substrate Engineering Strategy for Site‐Specific Enzymatic Fucosylation

Abstract

Fucosylation is one of the most common modifications of oligo-N-acetyllactosamine (oligo-Lac-NAc) glycans. However, none of known fucosyltransferases (FucTs) could install the α1,3-linked fucose to the oligo-LacNAc substrates in a site-specific manner. Here, we report a facile and general redox-controlled substrate engineering strategy for the site-specific α1,3-fucosylation of complex glycans containing multiple LacNAc units. This strategy takes advantage of an operationally simple oxidation enzyme module by using galactose oxidase (GOase) to convert the LacNAc unit into oxidized C6'-aldehyde LacNAc sequence, which is not a good substrate for recombinant α1,3-FucT from Helicobacter pylori strain 26695 (Hpα1,3FucT), enabling the site-specific α1,3-fucosylation at intact LacNAc sites. The general applicability and robustness of this strategy were demonstrated by the synthesis of a variety of structurally well-defined fucosides of linear and branched O-and N-linked glycans.

A Biomimetic Synthetic Strategy can Provide Keratan Sulfate I and II Oligosaccharides with Diverse Fucosylation and Sulfation Patterns

“…[53][54][55] Complex glycans can have several acceptor sites for a given glycosyltransferase making it difficult to prepare discrete compounds. Site selective glycosylations can, however, be accomplished by careful synthetic planning, 44 the use of unnatural sugar nucleotide donors, Asn chemical modifications [58][59][60] or temporary monosaccharide blocking groups. 41 Complex carbohydrates can be modified by entities such as sulfates, 61-63 however, methods to install such modifications in a site-specific manner are still lacking.…”