Molecular insights into the capsular polysaccharide transporter Wza-Wzc complex

Molecular insights into the capsular polysaccharide transporter Wza-Wzc complex | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Molecular insights into the capsular polysaccharide transporter Wza-Wzc complex Biao Yuan, Christian Sieben, Prateek Raj, Tina Rietschel, Rory Hennell James, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6993485/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Capsular polysaccharides (CPS), which form the protective outer capsule surrounding many Gram-negative bacterial pathogens, are critical virulence determinants. Their biosynthesis is primarily carried out via the conserved Wzx/Wzy-dependent pathway. In Escherichia coli, Group 1 CPS transport through the bacterial envelope is thought to be mediated by the Wza- Wzc complex. In this study, we present the first structural characterization of the complete Wza-Wzc complex from E. coli K12, determined using single-particle cryogenic electron microscopy. The structure revealed an elongated, continuous channel spanning the entire envelope, which is crucial for efficient CPS secretion, as supported by mutagenesis studies. Multiple structural snapshots of the ADP-bound Wza-Wzc complex captured intermediate conformations of the double membrane assembly, highlighting its remarkable intrinsic dynamics. In-depth analysis of the isolated Wza translocon and Wzc co-polymerase, revealed new mechanistic details of both complex formation and CPS transport. Importantly, we identified the jellyroll domain of Wzc as a previously unrecognized CPS-binding module, likely guiding CPS repeat units into a proposed Wzc-Wzy polymerization platform. Collectively, these findings provide new structural and functional insights into CPS synthesis and transport, advancing our understanding of bacterial capsule formation and virulence mechanisms. Bacteriology Full Text Additional Declarations The authors declare no competing interests. Supplementary Files 20250627sup.pdf Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6993485","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":477510149,"identity":"e527759e-2d56-47e6-b86d-d3ab6b5ed603","order_by":0,"name":"Biao Yuan","email":"data:image/png;base64,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","orcid":"","institution":"","correspondingAuthor":true,"prefix":"","firstName":"Biao","middleName":"","lastName":"Yuan","suffix":""},{"id":477510150,"identity":"77ce3196-d02d-45b1-a72e-afa8a0438a2d","order_by":1,"name":"Christian Sieben","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Christian","middleName":"","lastName":"Sieben","suffix":""},{"id":477510151,"identity":"eae86fda-68f3-471b-9108-c69a6c7dfba6","order_by":2,"name":"Prateek Raj","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Prateek","middleName":"","lastName":"Raj","suffix":""},{"id":477510152,"identity":"a450b1c3-c44a-41de-847e-71f13facdb1c","order_by":3,"name":"Tina Rietschel","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Tina","middleName":"","lastName":"Rietschel","suffix":""},{"id":477510153,"identity":"e7113315-9ff8-4324-958c-1654dcca8f93","order_by":4,"name":"Rory Hennell James","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Rory","middleName":"Hennell","lastName":"James","suffix":""},{"id":477510154,"identity":"f24c93ce-00b2-4c55-a51c-2d9c13ee6bcf","order_by":5,"name":"Anja Gatzemeier","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Anja","middleName":"","lastName":"Gatzemeier","suffix":""},{"id":477510155,"identity":"6b5621d5-c4d8-4490-8700-3743605182c7","order_by":6,"name":"Lothar Jänsch","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Lothar","middleName":"","lastName":"Jänsch","suffix":""},{"id":477510156,"identity":"341ca370-72af-4b44-b624-85b45ba990fd","order_by":7,"name":"Thomas C. 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