Alternative donor substrates for inverting and retaining glycosyltransferases

Area of Science:

• Biochemistry
• Carbohydrate Chemistry
• Enzymology

Background:

• Glycosyltransferases are crucial enzymes involved in the synthesis of complex carbohydrates.
• Understanding their catalytic mechanisms is essential for various biological and therapeutic applications.
• Natural glycosylation reactions typically involve specific anomeric configurations of donor substrates.

Purpose of the Study:

• To explore the catalytic capabilities of glycosyltransferases using non-natural glycosyl donors.
• To investigate the influence of aromatic leaving groups and anomeric configurations on glycosylation.
• To compare the activity of an inverting (Cst II) and a retaining (LgtC) glycosyltransferase.

Main Methods:

• Synthesis of novel glycosyl donors with aromatic leaving groups and varied anomeric configurations.
• Enzymatic assays using purified Cst II and LgtC glycosyltransferases.
• Analysis of glycosylation products formed with natural acceptor substrates and nucleotide cofactors.

Main Results:

• Both inverting (Cst II) and retaining (LgtC) glycosyltransferases successfully catalyzed glycosylation reactions with the novel donors.
• The use of aromatic leaving groups and opposite anomeric configurations did not prevent enzymatic activity.
• The study demonstrated the versatility of these enzymes in accepting modified substrates.

Conclusions:

• Glycosyltransferases can accommodate non-natural glycosyl donors with modified leaving groups and anomeric configurations.
• This finding expands the substrate scope for studying and potentially engineering glycosyltransferases.
• The results provide a foundation for developing new synthetic strategies in carbohydrate chemistry.