Glycoconjugate diversification in Campylobacter concisus is determined by two glycosyltransferases
Year: 2026
Type: article
Abstract: Bacterial glycoconjugates are structurally diverse, with enormous variation in sugar identity, modifications and linkages. Glycoconjugates play key roles in numerous cell functions, acting as the primary interface with the environment. Asparagine (N)-linked glycosylation has been extensively studied in the pathogenic Campylobacter genus, due to the availability of numerous genome sequences and the highly conserved pathway logic, despite the final N-linked glycan product diversity. We recently reported on a partitioning of N-linked glycan structures between the Campylobacter species, focused on the inclusion of a C6-carboxyl-sugar in the third position of the growing glycan in Campylobacter concisus. However, at the time, the final glycan was not fully defined. Here, we identify the final glycan product in C. concisus, demonstrating surprising substrate and linkage promiscuity of the GT-A enzyme, PglI, which adds the penultimate sugar, and uncover a previously uncharacterized enzyme (GT-25) that unexpectedly adds the final sugar to complete the heptasaccharide product. Through a detailed study of these two C. concisus pathway enzymes, the intermediate and final glycans were defined, with determination of linkage positions of major and minor isomeric products following each glycan addition, through high-resolution electronic excitation dissociation tandem mass spectrometry. These findings on the Group II C. concisus N-linked glycan highlight the diversification of the N-glycan structures across Campylobacter species and the utilization of GlcNAc over GalNAc at the non-reducing end, which is dominant in the Group I species.
Source: Journal of Biological Chemistry
Institutions: Boston University, Massachusetts Institute of Technology
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,430
Awards: Methods for determination of glycoprotein glycosylation similarities among disease states, High-Throughput De Novo Glycan Sequencing, A Thermo-Fisher Scientific Q-Exactive HF Mass Spectrometry System, Legacy Support During Closure of the Mass Spectrometry Resource for Biology and Medicine, Defining structure and function of GT-A fold enzymes in bacterial glycan assembly, Design and synthesis of nucleoside-based small molecules to inhibit phosphoglycosyl transferases, A Thermo-Fisher Scientific Orbitrap Fusion Lumos Tribrid Mass Spectrometer System, Deciphering the Principles of Membrane-Associated Glycan Assembly for Glycoconjugate Biosynthesis, Structure and function of the monotopic phosphoglycosyl transferase superfamily: Initiators of biosynthesis of complex bacterial glycoconjugates
OpenAlex ID: W7162412205