A phage encoded GapR nucleoid-associated protein binds a bacterial GapR to deactivate it via an inhibitory hetero-oligomer mechanism

A phage encoded GapR nucleoid-associated protein binds a bacterial GapR to deactivate it via an inhibitory hetero-oligomer mechanism | 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 Article A phage encoded GapR nucleoid-associated protein binds a bacterial GapR to deactivate it via an inhibitory hetero-oligomer mechanism Maria Schumacher, Raul Salinas, Sunny Yadav, Katie Leung, Porter Ellis, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8865587/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 Nucleoid associated proteins (NAPs) play key roles in bacterial chromosome organization and cellular processes. Recent work identified GapR as an essential NAP that is ubiquitous in α-proteobacteria. GapR structures reveal that the dimeric form of GapR can tetramerize in the presence of DNA to form a DNA-encasing clamp and data showed that GapR is required for bacterial replication as it recruits topoisomerases to regions of overtwisted DNA. Interestingly, diverse phages that infect α-proteobacteria encode GapR homologs. To gain insight into how phage GapRs may impact their cellular homologs we performed structure/function analyses on the roseobacterial and roseophage RDJLΦ1 GapR proteins. Crystal structures revealed that the RDJLΦ1 GapR harbors a structure different from the bacterial GapR that is incompatible with DNA binding. Cellular localization and fluorescence binding assays confirmed that the RDJLΦ1 phage GapR does not bind DNA. Strikingly, data show that the RDJLΦ1 GapR and bacterial GapR can form hetero-oligomers, suggesting that the RDJLΦ1 GapR may function as a GapR poison. Indeed, assays showed that the heterodimer forms is unable to bind DNA. Collectively these studies indicate a mechanism by which a phage encoded NAP can derail a host NAP to co-opt the cell and possibly favor phage infectious processes. Biological sciences/Structural biology/X-ray crystallography Biological sciences/Microbiology/Bacteriophages Full Text Additional Declarations There is NO Competing Interest. Supplementary Files NatcommSILASTFEB8Roseophage.pdf Supplementary information 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-8865587","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":604335459,"identity":"1d324477-a799-4267-8acb-cd7cc1575070","order_by":0,"name":"Maria 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