Dataset Information

Outer membrane utilisomes mediate oligosaccharide uptake in gut Bacteroidetes

ABSTRACT: Bacteroidetes are abundant members of the human microbiota, and species occupying the distal gut are capable of utilising a myriad of diet- and host-derived glycans. Transport of glycans across the outer membrane (OM) of these bacteria is mediated by SusCD protein complexes. Additionally, cell surface-exposed lipoproteins, namely surface glycan binding proteins and glycoside hydrolases, play critical roles in the capture and processing of large glycan chains into transport-competent substrates. Here we show that, for the levan and dextran utilisation systems of Bacteroides thetaiotaomicron, the additional OM components assemble on the core SusCD transporter, forming stable glycan utilising machines which we term ‘utilisomes’. Single particle electron cryogenic electron microscopy (cryo-EM) structures in the absence and presence of substrate reveal concerted conformational changes that rationalise the role of each component for efficient nutrient capture, as well as providing a direct demonstration of the pedal bin mechanism of substrate capture in the intact utilisome.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Bacteroides Thetaiotaomicron Bacteria

SUBMITTER: Matthias Trost

LAB HEAD: Matthias Trost

PROVIDER: PXD034863 | Pride | 2023-06-19

REPOSITORIES: Pride

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Publications

Outer membrane utilisomes mediate glycan uptake in gut Bacteroidetes.

White Joshua B R JBR Silale Augustinas A Feasey Matthew M Heunis Tiaan T Zhu Yiling Y Zheng Hong H Gajbhiye Akshada A Firbank Susan S Baslé Arnaud A Trost Matthias M Bolam David N DN van den Berg Bert B Ranson Neil A NA

Nature 20230607 7965

Bacteroidetes are abundant members of the human microbiota, utilizing a myriad of diet- and host-derived glycans in the distal gut<sup>1</sup>. Glycan uptake across the bacterial outer membrane of these bacteria is mediated by SusCD protein complexes, comprising a membrane-embedded barrel and a lipoprotein lid, which is thought to open and close to facilitate substrate binding and transport. However, surface-exposed glycan-binding proteins and glycoside hydrolases also play critical roles in the ...[more]

PMID: 37286596

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Project description:Various cancers such as colorectal cancer (CRC) are associated with alterations in protein glycosylation. CRC cell lines are frequently used to study these (glyco)biological changes and their mechanisms. However, differences between CRC cell lines with regard to their glycosylation have hitherto been largely neglected. Here, we comprehensively characterized the N-glycan profiles of 25 different CRC cell lines, derived from primary tumors and metastatic sites, in order to investigate their potential as glycobiological tumor model systems and to reveal glycans associated with cell line phenotypes. We applied an optimized, high-throughput membrane-based enzymatic glycan release for small sample amounts. Released glycans were derivatized to stabilize and differentiate between a2,3- and a2,6-linked N-acetylneuraminic acids, followed by N-glycosylation analysis by MALDI-TOF(/TOF)-MS. Our results showed pronounced differences between the N-glycosylation patterns of CRC cell lines. CRC cell line profiles differed from tissue-derived N-glycan profiles with regard to their high-mannose N-glycan content but showed a large overlap for complex type N-glycans, supporting their use as a glycobiological cancer model system. Importantly, we could show that the high-mannose N-glycans did not only occur as intracellular precursors but were also present at the cell surface. The obtained CRC cell line N-glycan features were not clearly correlated with mRNA expression levels of glycosyltransferases, demonstrating the usefulness of performing the structural analysis of glycans. Finally, correlation of CRC cell line glycosylation features with cancer cell markers and phenotypes revealed an association between highly fucosylated glycans and CDX1 and/or villin mRNA expression that both correlate with cell differentiation. Together, our findings provide new insights into CRC-associated glycan changes and setting the basis for more in-depth experiments on glycan function and regulation.

Dataset Information

Outer membrane utilisomes mediate oligosaccharide uptake in gut Bacteroidetes

Publications

Outer membrane utilisomes mediate glycan uptake in gut Bacteroidetes.

Similar Datasets

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