Saltor Núñez, L., Kumar, V. orcid.org/0000-0002-8825-3517, Ross, J.F. orcid.org/0000-0002-4784-103X et al. (5 more authors) (2025) Molecularly Defined Glycocalyx Models Reveal AB5 Toxins Recognize Their Target Glycans Superselectively. JACS Au. ISSN 2691-3704
Abstract
AB5 toxins are a class of bacterial toxins that recognize cell surface carbohydrates to facilitate their uptake by the target cell. Among them are cholera toxin (CT) from Vibrio cholerae that causes cholera, and Shiga toxin (STx) from Shigella dysenteriae and certain strains of Escherichia coli, which cause hemolytic uremic syndrome. While the glycolipid ligands for CT and STx (gangliosides GM1 and Gb3, respectively) have long been known, recent studies have shown that fucosylated structures, like Lewisx (Lex), also play a role in CT binding. This realization raises questions about the importance of interactions between these toxins and nonglycolipid components of the glycocalyx, which are not well understood. To address this challenge, we created glycocalyx models of defined thickness and tunable molecular composition through grafting of mucin-like glycopolymers on solid-supported lipid bilayers (SLBs). The synthesized mucin-like glycopolymers comprised a hyaluronic acid (HA) backbone, an anchor tag (biotin or hexa-histidine) at the HA reducing end, and side chains of relevant oligosaccharides (Lex, Gb3, or lactose) at defined densities. Analyses by quartz crystal microbalance with dissipation monitoring and spectroscopic ellipsometry provided quantification of the thickness, mesh size, and target glycan concentration of the glycocalyx models and of toxin binding kinetics. The B subunit pentamers of both CT and STx showed significantly enhanced affinity in the model glycocalyx environment due to multivalent binding to their respective target glycans. Most notably, toxin binding increased superlinearly with the concentration of the target glycan in the model glycocalyx. We propose that such “superselective” binding is an important factor in host cell selection. Our approach provides a new set of tools to make designer glycocalyces and analyze multivalent protein-glycan interactions in a controlled environment.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2025 The Authors. This is an open access article under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | synthetic glycocalyx, biomimetic interfaces, lectin binding, glycoconjugate, superselectivity, QCM-D |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biomedical Sciences (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Molecular and Cellular Biology (Leeds) |
Funding Information: | Funder Grant number BBSRC (Biotechnology & Biological Sciences Research Council) BB/X00158X/1 EU - European Union 814029 Leverhulme Trust RPG-2018-100 |
Depositing User: | Symplectic Publications |
Date Deposited: | 23 May 2025 10:14 |
Last Modified: | 23 May 2025 10:14 |
Status: | Published online |
Publisher: | American Chemical Society |
Identification Number: | 10.1021/jacsau.5c00305 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:227020 |