Neo-Glycoproteins
The platform of multivalent presentation of glycans is extended by usage of non-glycosylated serum proteins, e.g. bovine serum albumin (BSA). In a two-stage process, functional groups of amino acids side chains (e.g. NH2-) are specifically conjugated with synthesized glycans. The conjugation proceeds under mild conditions in aqueous milieu at room temperature without affecting protein or glycan structure. Analysis of artificially glycosylated proteins (neo-glycoproteins) is achieved by an in-house optimized biochemical assay (TNBS Assay) or via SDS polyacrylamide gel electrophoresis.
The number of conjugated glycan per protein molecule (multivalence) is tunable. Thereby, the interaction strength (avidity) of lectins can be modulated. The investigated galectins and bacterial toxins bind with high avidity and specificity of the multivalent neo-glycoproteins.
Papers reporting the synthesis and application of neo-glycoproteins:
Böcker, S., Laaf, D., Elling, L., 2015. Galectin Binding to Neo-Glycoproteins: LacDiNAc Conjugated BSA as Ligand for Human Galectin-3. Biomolecules 5, 1671-1696. https://doi.org/10.3390/biom5031671.
Böcker, S., Elling, L., 2017. Biotinylated N-Acetyllactosamine- and N,N-Diacetyllactosamine-Based Oligosaccharides as Novel Ligands for Human Galectin-3. BioEng. 4, 31. https://doi.org/10.3390/bioengineering4020031.
Fischöder, T., Laaf, D., Dey, C., Elling, L., 2017. Enzymatic Synthesis of N-Acetyllactosamine (LacNAc) Type 1 Oligomers and Characterization as Multivalent Galectin Ligands. Molecules 22, 1320. https://doi.org/10.3390/molecules22081320.
Laaf, D., Bojarová, P., Mikulová, B., Pelantová, H., Křen, V., Elling, L., 2017. Two-Step Enzymatic Synthesis of β-D-N-Acetylgalactosamine-(1→4)-D-N-acetylglucosamine (LacdiNAc) Chitooligomers for Deciphering Galectin Binding Behavior. Adv. Synth. Catal. 359, 2101-2108. https://doi.org/10.1002/adsc.201700331.
Laaf, D., Bojarová, P., Pelantová, H., Křen, V., Elling, L., 2017. Tailored Multivalent Neo-Glycoproteins: Synthesis, Evaluation, and Application of a Library of Galectin-3-Binding Glycan Ligands. Bioconj. Chem. 28, 2832-2840. https://doi.org/10.1021/acs.bioconjchem.7b00520.
Laaf, D., Steffens, H., Pelantová, H., Bojarová, P., Křen, V., Elling, L., 2017. Chemo-Enzymatic Synthesis of Branched N-Acetyllactosamine Glycan Oligomers for Galectin-3 Inhibition. Adv. Synth. Catal. 359, 4015-4024. https://doi.org/10.1002/adsc.201700969.
Bumba, L., Laaf, D., Spiwok, V., Elling, L., Křen, V., Bojarová, P., 2018. Poly-N-Acetyllactosamine Neo-Glycoproteins as Nanomolar Ligands of Human Galectin-3: Binding Kinetics and Modeling. Internat. J. Mol. Sci. 19, 372. https://doi.org/10.3390/ijms19020372.
Zhang, H., Laaf, D., Elling, L., Pieters, R.J., 2018. Thiodigalactoside-Bovine Serum Albumin Conjugates as High-Potency Inhibitors of Galectin-3: An Outstanding Example of Multivalent Presentation of Small Molecule Inhibitors. Bioconj. Chem. 29, 1266-1275. https://doi.org/10.1021/acs.bioconjchem.8b00047.
Heine, V., Boesveld, S., Pelantova, H., Kren, V., Trautwein, C., Strnad, P., Elling, L., 2019. Identifying Efficient Clostridium difficile Toxin A Binders with a Multivalent Neo-Glycoprotein Glycan Library. Bioconj. Chem. 30, 2373-2383. https://doi.org/10.1021/acs.bioconjchem.9b00486.
Hoffmann, M., Hayes, M.R., Pietruszka, J., Elling, L., 2020. Synthesis of the Thomsen-Friedenreich-antigen (TF-antigen) and binding of Galectin-3 to TF-antigen presenting neo-glycoproteins. Glycoconjugate J. 37, 457-470. https://doi.org/10.1007/s10719-020-09926-y.
Heine, V., Hovorková, M., Vlachová, M., Filipová, M., Bumba, L., Janoušková, O., Hubálek, M., Cvačka, J., Petrásková, L., Pelantová, H., Křen, V., Elling, L., Bojarová, P., 2021. Immunoprotective neo-glycoproteins: Chemoenzymatic synthesis of multivalent glycomimetics for inhibition of cancer-related galectin-3. Eur. J. Med. Chem. 220, 113500. https://doi.org/10.1016/j.ejmech.2021.113500.
V. Heine, T. Kremers, N. Menzel, U. Schnakenberg, L. Elling (2021). Electrochemical Impedance Spectroscopy Biosensor Enabling Kinetic Monitoring of Fucosyltransferase Activity. ACS Sensors 6, 1003-1011. https://doi.org/10.1021/acssensors.0c02206