Extension of N- and O-glycans with linear sialic acid polymers (polySias) was described on a limited number of mammalian glycoproteins, including the α2,8-polysialyltransferases ST8Sia II and ST8Sia IV. Previous in vitro analyses have shown that ST8Sia IV from the salmonid fish Coregonus maraena (Cma) had high polysialylation activity and broader donor substrate specificity compared to its human counterpart. In this study, we investigated whether the fish ST8Sia IV was able to polysialylate N- and O-glycans of glycoproteins with a focus on its autopolysialylation capacity. Using a combination of strategies, including plant-based glycoengineering, we found that the Cma ST8Sia IV is able to use both types of acceptors for the formation of long polySia chains with a degree of polymerization of >40 consisting of N-acetylneuraminic acid and N-glycolylneuraminic acid. Given the importance of polySias in multiple health and disease states, the Cma ST8Sia IV represents a useful biocatalyst with applications in the fields of biosafe therapeutics and glycobiology.

Cells are coated with glycans that are linked to cellular recognition via sialic acid-binding immunoglobulin-like lectins (Siglecs). Here the authors present a resource characterising human Siglec exp...

Sialic acids are the terminal monosaccharides of the glycocalyx that critically shape cell-cell interactions, and are strongly implicated in regulating immune recognition and tissue homeostasis. In ca...

Siglec-liposomes are a multivalent and modular platform for profiling Siglec ligands and modulating immune cell function.

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Interactions between glycan-binding proteins (GBPs) and carbohydrates (glycans) are essential to many biological processes relevant to human health and disease. For most GBPs, however, their glycan i...

Siglecs are immunomodulatory receptors that regulate immune cell function. A fundamental challenge in studying Siglec-ligand interactions is the low affinity of Siglecs for their ligands. Inspired by ...

Siglec-10 is a sialic acid-binding immunoglobulin-like lectin implicated in immune regulation, yet its molecular basis for ligand recognition and functional role in immune modulation remain poorly def...