Gray, DA, White, JBR, Oluwole, AO et al. (13 more authors) (2021) Insights into SusCD-mediated glycan import by a prominent gut symbiont. Nature Communications, 12 (1). 44. ISSN 2041-1723
Abstract
In Bacteroidetes, one of the dominant phyla of the mammalian gut, active uptake of large nutrients across the outer membrane is mediated by SusCD protein complexes via a “pedal bin” transport mechanism. However, many features of SusCD function in glycan uptake remain unclear, including ligand binding, the role of the SusD lid and the size limit for substrate transport. Here we characterise the β2,6 fructo-oligosaccharide (FOS) importing SusCD from Bacteroides thetaiotaomicron (Bt1762-Bt1763) to shed light on SusCD function. Co-crystal structures reveal residues involved in glycan recognition and suggest that the large binding cavity can accommodate several substrate molecules, each up to ~2.5 kDa in size, a finding supported by native mass spectrometry and isothermal titration calorimetry. Mutational studies in vivo provide functional insights into the key structural features of the SusCD apparatus and cryo-EM of the intact dimeric SusCD complex reveals several distinct states of the transporter, directly visualising the dynamics of the pedal bin transport mechanism.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Author(s) 2021. This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) (https://creativecommons.org/licenses/by/4.0/) |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Molecular and Cellular Biology (Leeds) > Cryo EM, Image Processing (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 15 Jan 2021 14:49 |
Last Modified: | 25 Jun 2023 22:33 |
Status: | Published |
Publisher: | Nature Research |
Identification Number: | 10.1038/s41467-020-20285-y |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:170069 |