Insight into glycosphingolipid crypticity: Crystal structure of the anti-tumor antibody 14F7 and recognition of NeuGc GM3 ganglioside

Bjerregaard-Andersen, K.; Johannesen, H.; Abraha, F.; Sakanovic, A.; Grosser, D.; Coskun, U.; Anderluh, G.; Oscarson, S.; Moreno, E.; Grzybek, M.; Krengel, U.

doi:10.1101/2020.09.18.294777

bioRxiv · 10.1101/2020.09.18.294777

Insight into glycosphingolipid crypticity: Crystal structure of the anti-tumor antibody 14F7 and recognition of NeuGc GM3 ganglioside

Bjerregaard-Andersen, K.·Johannesen, H.·Abraha, F.·Sakanovic, A.·Grosser, D.·Coskun, U.·Anderluh, G.·Oscarson, S.·Moreno, E.·Grzybek, M.·Krengel, U.

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Abstract

Tumor-associated glycolipids such as NeuGc GM3 are auspicious molecular targets in antineoplastic therapies and vaccine strategies. 14F7 is an anti-tumor antibody with high clinical potential, which has extraordinary specificity for NeuGc GM3, but does not recognize the very similar, ubiquitous NeuAc GM3. Here we present the 2.3 [A] crystal structure of the 14F7 binding domain (14F7 scFv) in complex with the NeuGc GM3 trisaccharide. Intriguingly, a water molecule appears to shape the specificity of 14F7. Using model membrane systems, we show that 14F7 recognizes NeuGc GM3 only above lipid concentrations that are likely to form glycolipid-rich domains. This "all-or-nothing" effect was exacerbated in giant unilamellar vesicles and multilamellar vesicles, whereas no binding was observed to 100 nm liposomes, emphasizing that the 14F7-NeuGc GM3 interaction is additionally modulated by membrane curvature. Unexpectedly, adding NeuAc GM3 strongly increased binding affinity to NeuGc GM3-containing liposomes. This effect may be important for tumor recognition, where the ubiquitous NeuAc GM3 may enhance 14F7 binding to NeuGc GM3-expressing cancer cells.

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Bjerregaard-Andersen, K., Johannesen, H., Abraha, F., Sakanovic, A., Grosser, D., Coskun, U., Anderluh, G., Oscarson, S., Moreno, E., Grzybek, M., Krengel, U.. 2020-09-18. Insight into glycosphingolipid crypticity: Crystal structure of the anti-tumor antibody 14F7 and recognition of NeuGc GM3 ganglioside. https://doi.org/10.1101/2020.09.18.294777

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