Showing papers by "Saurabh Srivastava published in 2021"
TL;DR: In this article, the authors used a set of naturally-evolved microbial molecules (bacterial adhesins, toxin subunits and viral hemagglutinininesterases) that recognize sialoglycans with defined specificity to delineate 9 classes of Sialoglycan Recognizing Probes (SGRPs: SGRP1-SGRP9) that can be used to explore mammalian sialome changes in a simple and systematic manner.
Abstract: Glycans that are abundantly displayed on vertebrate cell surface and secreted molecules are often capped with terminal sialic acids (Sias). These diverse 9-carbon-backbone monosaccharides are involved in numerous intrinsic biological processes. They also interact with commensals and pathogens, while undergoing dynamic changes in time and space, often influenced by environmental conditions. However, most of this sialoglycan complexity and variation remains poorly characterized by conventional techniques, which often tend to destroy or overlook crucial aspects of Sia diversity and/or fail to elucidate native structures in biological systems i.e., in the intact sialome. To date, in situ detection and analysis of sialoglycans has largely relied on the use of plant lectins, sialidases or antibodies, whose preferences (with certain exceptions) are limited and/or uncertain. We took advantage of naturally-evolved microbial molecules (bacterial adhesins, toxin subunits and viral hemagglutinin-esterases) that recognize sialoglycans with defined specificity to delineate 9 classes of Sialoglycan Recognizing Probes (SGRPs: SGRP1–SGRP9) that can be used to explore mammalian sialome changes in a simple and systematic manner, using techniques common in most laboratories. SGRP candidates with specificity defined by sialoglycan microarray studies were engineered as tagged probes, each with a corresponding non-binding mutant probe as a simple and reliable negative control. The optimized panel of SGRPs can be used in methods commonly available in most bioscience labs, such as ELISA, Western Blot, flow cytometry and histochemistry. To demonstrate the utility of this approach, we provide examples of sialoglycome differences in tissues from C57BL/6 wild type mice and human-like Cmah−/− mice.
5 citations
TL;DR: In this paper, a 9-digit code for trisaccharides with terminal Sias and underlying two monosaccharide assigned from the non-reducing end was devised.
Abstract: Vertebrate sialic acids (Sias) display much diversity in modifications, linkages and underlying glycans. Slide microarrays allow high-throughput analysis of sialoglycan-protein interactions. The preceding paper used ~150 structurally-defined sialyltrisaccharides with various Sias and modified forms at non-reducing ends, to compare pentameric sialoglycan-recognizing bacterial toxin B subunits. Unlike the poor correlation between B subunits and species phylogeny, there is stronger correlation with Sia types prominently expressed in susceptible species. 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). Given library size, data sorting and analysis posed a challenge. We devised a 9-digit code for trisaccharides with terminal Sias and underlying two monosaccharides assigned from the non-reducing end, with three digits assigning a monosaccharide, its modifications, and linkage. This code allows logical sorting, motif searching of results, and optimizes printing. While we developed the system for the >113,000 possible linear sialyltrisaccharides, we note that a biantennary N-glycan with two terminal sialoglycan trisaccharides could 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. Thus, while glycomic approaches address these challenges, naturally-occurring toxin B subunits are simpler tools to track the dynamic sialome in biological systems.