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Here, the authors present cryoEM structures of AftB, a key mycobacterial enzyme that adds terminal arabinose residues to the cell wall. In concert with functional assays and MD simulations, mechanistic insights are presented.

Here the authors investigate of the structural basis of substrate recognition and the catalytic mechanism of the mannosyltransferase PimE, which is crucial for the biosynthesis of phosphatidyl-myo-inositol mannosides (PIMs) in Mycobacterium tuberculosis.

Cellular glycosylation is complex and heterogeneous, which is challenging to reproduce synthetically. Here, the authors report on enzymatic remodelling of multivalent glycosylated bacteriophages to produce genetically encoded library of N-glycans which can be used to measure glycan-protein interactions with lectins on the surface of live cells and organs.

Siglec-glycolipid interactions are often studied outside the context of a lipid bilayer. Here, the authors combine a variety of chemical biology techniques to demonstrate a unique and physiologically relevant ability of Siglec-6 to recognize glycolipids in a membrane.

Some Salmonella isolates produce an enigmatic, transient antigen known as T1. Here, Kelly et al. show that T1 is a complex linear glycan linked to lipid A–core, like a typical O antigen, and is expressed in a phase-variable manner regulated by recombinational inversion of a promoter upstream of the T1 genetic locus.

Mass spectrometric profiling of a glycan library reveals that sialylated glycans, especially sialic acid-containing gangliosides, interact with the RBD of the SARS-CoV-2 spike protein and are involved in ACE2-dependent viral infection.

The enzymes that link bacterial capsule polymers to the outermembrane glycolipids, termed transition transferases, are identified, enabling reconstruction of the entire capsule biosynthesis pathway.

Ribofuranose residues are installed on O-antigens of bacterial polysaccharides by a dual-activity enzyme that uses phosphoribosyl-5-phospho-d-ribosyl-α-1-diphosphate as a sugar donor and also catalyzes phosphate hydrolysis.

Liquid glycan arrays (LiGAs), presented on M13 bacteriophage surface proteins through bioorthogonal chemistry, link surface glycans to genetic barcodes in phage DNA, enabling lectin–glycan interaction profiling by DNA sequencing.

The cryo-EM structure of Mycobacterium smegmatis arabinosyltransferase B EmbB involved in mycobacterial cell wall biosynthesis provides insights into the substrate binding and reaction mechanism. Mapping of the ethambutol resistance associated mutations onto the structure suggests the location of the drug binding site.

WbbB is a structurally unusual retaining glycosyltransferase. Here, the authors show that WbbB forms an Asp232-Kdo adduct prior to transfer to the saccharide acceptor. Therefore, unlike any previously studied glycosyltransferase, WbbB uses the double-displacement mechanism first proposed in 1953.

Reconstitution of β-Kdo-based capsular polysaccharide biosynthesis and crystallographic analysis of KpsC, a glycosyltransferase with two active sites for β-Kdo-glycolipid primer extension, reveal a new glycosyltransferase structural family.

Structural characterization of WbbM, an enzyme involved in O2a-antigen biosynthesis in Klebsiella pneumoniae, reveals two unique active sites with galactopyranosyl- or galactofuranosyl-transferase activities for oligosaccharide polymerization.

Elise Ishida et al. generate human monoclonal antibodies that can selectively recognize specific oligosaccharide epitopes of the polysaccharides arabinomannan and lipoarabinomannan, which are critical for M. tuberculosis pathogenesis. The authors demonstrate the utility of these antibodies in both diagnostic and laboratory settings, making them important tools for M. tuberculosis research.