Sialoglycan microarray encoding reveals differential sialoglycan binding of phylogenetically-related bacterial AB5 toxin B subunits

Sasmal, A.; Khan, N.; Khedri, Z.; Kellman, B. P.; Srivastava, S.; Verhagen, A.; Yu, H.; Bruntse, A. B.; Diaz, S.; Varki, N.; Beddoe, T.; Paton, A. W.; Paton, J. C.; Chen, X.; Lewis, N. E.; Varki, A.

doi:10.1101/2021.05.28.446191

bioRxiv · 10.1101/2021.05.28.446191

Sialoglycan microarray encoding reveals differential sialoglycan binding of phylogenetically-related bacterial AB5 toxin B subunits

Sasmal, A.·Khan, N.·Khedri, Z.·Kellman, B. P.·Srivastava, S.·Verhagen, A.·Yu, H.·Bruntse, A. B.·Diaz, S.·Varki, N.·Beddoe, T.·Paton, A. W.·Paton, J. C.·Chen, X.·Lewis, N. E.·Varki, A.

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Abstract

Vertebrate sialic acids (Sias) display much diversity in modifications, linkages and underlying glycans. Slide microarrays allow high-throughput explorations of sialoglycan-protein interactions. A microarray presenting [~]150 structurally-defined sialyltrisaccharides with various Sias linkages and modifications still poses challenges in planning, data sorting, visualization and analysis. To address these issues, we devised a simple 9-digit code for sialyltrisaccharides with terminal Sias and underlying two monosaccharides assigned from the non-reducing end, with three digits assigning a monosaccharide, its modifications, and linkage. Calculations based on the encoding system reveals >113,000 likely linear sialyltrisaccharides in nature. Notably a biantennary N-glycan with two terminal sialyltrisaccharides could thus have >1010 potential combinations and a triantennary N-glycan with three terminal sequences, >1015 potential combinations. While all possibilities likely do not exist in nature, sialoglycans encode enormous diversity. While glycomic approaches are used to probe such diverse sialomes, naturally-occurring bacterial AB5 toxin B subunits are simpler tools to track the dynamic sialome in biological systems. Sialoglycan microarray was utilized to compare sialoglycan-recognizing bacterial toxin B subunits. Unlike the poor correlation between B subunits and species phylogeny, there is stronger correlation with Sia-epitope preferences. Further supporting this pattern, we report a B subunit (YenB) from Yersinia enterocolitica (broad host range) recognizing almost all sialoglycans in the microarray, including 4-O-acetylated-Sias not recognized by a Y. pestis orthologue (YpeB). Differential Sia-binding patterns were also observed with phylogenetically-related B subunits from Escherichia coli (SubB), Salmonella Typhi (PltB), S. Typhimurium (ArtB), extra-intestinal E.coli (EcPltB), Vibrio cholera (CtxB), and cholera family homologue of E. coli (EcxB).

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Sasmal, A., Khan, N., Khedri, Z., Kellman, B. P., Srivastava, S., Verhagen, A., Yu, H., Bruntse, A. B., Diaz, S., Varki, N., Beddoe, T., Paton, A. W., Paton, J. C., Chen, X., Lewis, N. E., Varki, A.. 2021-05-29. Sialoglycan microarray encoding reveals differential sialoglycan binding of phylogenetically-related bacterial AB5 toxin B subunits. https://doi.org/10.1101/2021.05.28.446191

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