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

Area of Science:

• Biochemistry
• Glycobiology
• Enzymology

Background:

• Fucosylation is a common glycan modification, crucial for biological processes.
• Existing fucosyltransferases (FucTs) lack site-specificity for alpha1,3-fucosylation on oligo-N-acetyllactosamine (oligo-LacNAc) substrates.
• Precise control over glycan structure is essential for understanding and manipulating biological functions.

Purpose of the Study:

• To develop a general and facile strategy for site-specific alpha1,3-fucosylation of complex glycans.
• To overcome the limitations of current fucosyltransferases in achieving regioselective fucosylation.
• To enable the synthesis of well-defined fucosylated glycans for further research.

Main Methods:

• Employed a redox-controlled substrate engineering approach.
• Utilized galactose oxidase (GOase) to selectively oxidize oligo-LacNAc units to an aldehyde intermediate.
• Leveraged the engineered substrate's altered reactivity with recombinant alpha1,3-FucT from Helicobacter pylori (Hpα1,3FucT) for site-specific fucosylation.

Main Results:

• Demonstrated a robust method for site-specific alpha1,3-fucosylation of oligo-LacNAc.
• Successfully synthesized various structurally defined fucosides of linear and branched O- and N-linked glycans.
• The engineered oxidized LacNAc unit selectively directed fucosylation to intact LacNAc sites.

Conclusions:

• The developed strategy provides a powerful tool for the site-specific synthesis of complex fucosylated glycans.
• This approach offers broad applicability for engineering diverse glycan structures.
• The method overcomes previous limitations in achieving regioselective alpha1,3-fucosylation, advancing glycan synthesis and research.