Synthesis of asparagine-linked bacillosamine

Area of Science:

• Microbiology
• Glycobiology
• Organic Chemistry

Background:

• Protein glycosylation is a crucial post-translational modification found in various organisms.
• N-linked glycosylation, previously thought to be rare in prokaryotes, has been identified in the pathogen Campylobacter jejuni.
• The glycan structure in C. jejuni is unique, featuring specific sugar residues and an N-glycosidic linkage to asparagine.

Purpose of the Study:

• To investigate the unique N-linked glycan structure in Campylobacter jejuni.
• To synthesize the key component, 2,4-diacetamido-2,4,6-trideoxy-d-glucopyranose (bacillosamine; Bac).
• To establish the Asn-linked form of this unique glycan.

Main Methods:

• Chemical synthesis of bacillosamine (Bac) from a 2-azido-2-deoxy-D-galactose derivative.
• Conversion of the synthesized Bac into an Asn-linked glycan structure.
• Analysis of the synthesized glycan structure and linkage.

Main Results:

• Successful synthesis of the unique bacillosamine (Bac) sugar residue.
• Demonstration of the chemical feasibility of creating the Asn-linked glycan structure.
• Confirmation of the unique glycan composition involving GalNAc, Glc, and Bac.

Conclusions:

• The synthesis of the unique N-linked glycan from Campylobacter jejuni is achievable.
• This study provides a chemical basis for understanding the biosynthesis and structure of prokaryotic N-linked glycoproteins.
• The synthetic approach can be valuable for further studies on Campylobacter jejuni glycosylation and its biological implications.