Unmasking Sialoglycan Specificity: How CatchAll Glycan Array Empowered a Breakthrough in Glycan Probe Design

A deeper look at Liang et al. (2025) and how CatchAll helped reshape the glycan profiling toolkit

In the field of glycoscience, the ability to specifically detect and study individual glycan motifs -such as sialoglycans – is crucial for advancing both basic research and translational applications. Sialic acids, including Neu5Ac, Neu5Gc, and Kdn, cap the ends of glycan chains on glycoproteins and glycolipids, influencing key biological processes like immune modulation, pathogen interaction, and cancer progression.

Yet, the tools used to study these sugars – lectins, antibodies, and commercially engineered glycan binders – have often fallen short in terms of specificity, reproducibility, and structural coverage. Plant lectins like SNA and MAL-II bind broadly and sometimes unpredictably; glycantargeting antibodies are difficult to raise and validate, especially given the low immunogenicity and high structural similarity of glycans.

The recent study by Liang et al., published in Nature Communications (2025), presents a creative and highly effective solution: engineering mutant bacterial glycosidases into stable, high-affinity glycan-binding probes. This platform, termed GRABs (Glycan Recombinant Affinity Binders), offers a transformative approach to glycan labeling and analysis – especially for sialoglycans.

Turning Enzymes into Glycan-Specific Binders

The GRABs developed in this study are based on sialidases from Streptococcus pneumoniae (SpNanA) and Ruminococcus gnavus (RgNanH). These enzymes naturally cleave terminal sialic acids from glycans. Liang et al. targeted key catalytic residues and engineered mutant forms (e.g., SpNanA^D372N, RgNanH^D282A) that retain high-affinity glycan recognition but are catalytically inactive – effectively transforming enzymes into pure binding proteins.

• GRAB-Sia: Derived from SpNanA, binds a broad range of sialoglycans regardless of linkage (α2,3, α2,6, α2,8).
• GRAB-Sia3: Derived from RgNanH, specifically binds α2,3-linked sialoglycans with minimal off-target recognition.

To boost binding avidity and enable multivalent interactions, both were further tetramerized via streptavidin to form tetra-GRABs.

CatchAll Glycan Array: Enabling Definitive Sialoglycan Profiling

While these engineered probes showed promising activity in flow cytometry and blotting, the authors faced a crucial question: Do these GRABs truly discriminate between glycan linkages, and how comprehensive is their binding profile?

To answer this, they used the CatchAll Glycan Array, our extensively curated platform containing 166 structurally diverse glycans.

 

 

Figure A shows binding of tetrameric GRAB-Sia to a broad spectrum of sialoglycans, including both α2,3- and α2,6-linked sialylated motifs, with minimal off-target binding to sulfated or non-sialylated glycans.

Figure B, by contrast, demonstrates exclusive binding of GRAB-Sia3 to α2,3-linked sialoglycans, highlighting its linkage-specific selectivity and ruling out recognition of α2,6 or α2,8 variants.

The figures are reproduced from Liang, S., et al. “Mutant glycosidases for labeling sialoglycans with high specificity and affinity.” Nature Communications, 16, 1427 (2025).

This level of profiling would not be possible without the high-resolution structural diversity offered by CatchAll. In fact, it was our array that enabled the researchers to: (1) Distinguish fine linkage specificity; (2) Identify binding gaps due to steric hindrance (e.g., branched sialoglycans); and (3) Validate biological selectivity of GRABs before in vivo deployment.

For researchers developing novel glycan binders or validating monoclonal antibodies, CatchAll eliminates ambiguity by offering a gold-standard, quantitative view of glycan recognition.

Empowering the Next Generation of Glycan Research

At the heart of every major discovery in glycobiology lies a simple truth: you can’t understand what you can’t measure. The CatchAll™ Glycan Array was designed to meet this need – giving scientists an expansive, unbiased, and reproducible platform to profile glycan interactions at scale. Whether you are engineering new glycan binders like GRABs; characterizing glycanantibody interactions; exploring immune checkpoint mechanisms via Siglec ligands; or mapping the glycome of a novel cell line or tissue type, CatchAll lets you see the full picture. With robust structure diversity, minimal background signal, and flexible formats, it empowers confident discovery from day one.