Actinomycin analogs from soil-derived Streptomyces sp. PSU-S4-23 with activity against MRSA

Actinomycin analogs from soil-derived Streptomyces sp. PSU-S4-23 with activity against MRSA | 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 Actinomycin analogs from soil-derived Streptomyces sp. PSU-S4-23 with activity against MRSA Chollachai Klaysubun, Kamonnut Singkhamanan, Monwadee Wonglapsuwan, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7993493/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 Genome-based discovery provides a powerful approach for identifying bioactive natural products. Using this approach, we identified actinomycin production in Streptomyces sp. PSU-S4-23. The genome contains a nonribosomal peptide synthetase (NRPS) biosynthetic gene cluster closely matching the actinomycin D reference (BGC0000296), including two NRPS genes encoding the canonical five-module assembly line and a neighboring cytochrome P450 consistent with oxidative tailoring. Culture extracts were tested and showed antibacterial activity against Gram-positive species Staphylococcus aureus (both MSSA and MRSA), Bacillus subtilis, Bacillus cereus, Enterococcus faecalis , and Staphylococcus epidermidis with additional inhibition of the Gram-negative pathogens Pseudomonas aeruginosa and Acinetobacter baumannii in agar diffusion assays. LC–MS/MS profiling of active fractions revealed a tight chromatographic window with ions diagnostic for actinomycins, featuring [M + H] + at m/z 1,269.6, 1,255.6, and 1,271.6 corresponding to actinomycin X 2 , actinomycin D, and actinomycin I, respectively. Comparative genomics placed PSU-S4-23 within Streptomyces and closest to S. caeni CGMCC 4.7426 T , while ANIb (94.69%) and dDDH (68.2%) values were below species thresholds, indicating a distinct lineage. Overall, the agreement between the actinomycin-like BGC and LC–MS/MS evidence establishes Streptomyces sp. PSU-S4-23 as a producer of actinomycin analogs, predominantly actinomycin X 2 and underscores genome mining as an efficient strategy to prioritize strains for antibiotic discovery. Full Text Additional Declarations No competing interests reported. Supplementary Files Supplementarydata.docx 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7993493","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":537770378,"identity":"d819dac1-e825-4847-98e0-58fd82636282","order_by":0,"name":"Chollachai Klaysubun","email":"","orcid":"","institution":"Prince of Songkla University","correspondingAuthor":false,"prefix":"","firstName":"Chollachai","middleName":"","lastName":"Klaysubun","suffix":""},{"id":537770379,"identity":"6bdec02a-89c2-4c0b-962c-a6ce4d8743fe","order_by":1,"name":"Kamonnut Singkhamanan","email":"","orcid":"","institution":"Prince of Songkla 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PSU-S4-23 with activity against MRSA","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7993493/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7993493/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eGenome-based discovery provides a powerful approach for identifying bioactive natural products. Using this approach, we identified actinomycin production in \u003cem\u003eStreptomyces\u003c/em\u003e sp. PSU-S4-23. The genome contains a nonribosomal peptide synthetase (NRPS) biosynthetic gene cluster closely matching the actinomycin D reference (BGC0000296), including two NRPS genes encoding the canonical five-module assembly line and a neighboring cytochrome P450 consistent with oxidative tailoring. Culture extracts were tested and showed antibacterial activity against Gram-positive species \u003cem\u003eStaphylococcus aureus\u003c/em\u003e (both MSSA and MRSA), \u003cem\u003eBacillus subtilis, Bacillus cereus, Enterococcus faecalis\u003c/em\u003e, and \u003cem\u003eStaphylococcus epidermidis\u003c/em\u003e with additional inhibition of the Gram-negative pathogens \u003cem\u003ePseudomonas aeruginosa\u003c/em\u003e and \u003cem\u003eAcinetobacter baumannii\u003c/em\u003e in agar diffusion assays. LC\u0026ndash;MS/MS profiling of active fractions revealed a tight chromatographic window with ions diagnostic for actinomycins, featuring [M\u0026thinsp;+\u0026thinsp;H]\u003csup\u003e+\u003c/sup\u003e at m/z 1,269.6, 1,255.6, and 1,271.6 corresponding to actinomycin X\u003csub\u003e2\u003c/sub\u003e, actinomycin D, and actinomycin I, respectively. Comparative genomics placed PSU-S4-23 within \u003cem\u003eStreptomyces\u003c/em\u003e and closest to \u003cem\u003eS. caeni\u003c/em\u003e CGMCC 4.7426\u003csup\u003eT\u003c/sup\u003e, while ANIb (94.69%) and dDDH (68.2%) values were below species thresholds, indicating a distinct lineage. Overall, the agreement between the actinomycin-like BGC and LC\u0026ndash;MS/MS evidence establishes \u003cem\u003eStreptomyces\u003c/em\u003e sp. PSU-S4-23 as a producer of actinomycin analogs, predominantly actinomycin X\u003csub\u003e2\u003c/sub\u003e and underscores genome mining as an efficient strategy to prioritize strains for antibiotic discovery.\u003c/p\u003e","manuscriptTitle":"Actinomycin analogs from soil-derived Streptomyces sp. 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