Structural basis for energy transfer and electron transport in the photosystem I-ferredoxin-NADP+ reductase supercomplex from Nannochloropsis oceanica

Structural basis for energy transfer and electron transport in the photosystem I-ferredoxin-NADP+ reductase supercomplex from Nannochloropsis oceanica | 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 Structural basis for energy transfer and electron transport in the photosystem I-ferredoxin-NADP + reductase supercomplex from Nannochloropsis oceanica Xiaowei Pan, Yue Qiu, Hui Shang, Ruiqi Shao, Qingyang Li, Jiaqi Meng, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8964687/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract In photosynthetic linear electron flow (LEF), photosystem I (PSI) transfers electrons to its stromal acceptor ferredoxin (Fd), which are then delivered to ferredoxin–NADP⁺ reductase (FNR) for NADPH production. The marine stramenopile alga Nannochloropsis oceanica (N. oceanica) is noted for its high lipid content, bioenergy potential, and elevated LEF activity. Its PSI associates with a light-harvesting complex I known as the violaxanthin-chlorophyll a-protein (VCP). Here, we present structural and biochemical evidence that NoPSI-VCP directly binds FNR on the stromal side, which may account for the significantly enhanced LEF activity of N. oceanica. The cryo-EM structure of the NoPSI-VCP-FNR supercomplex, resolved at 2.89 Å resolution, shows that FNR interacts with core subunits PsaB, PsaD, PsaI, and PsaL through an extended N terminal domain, representing a previously unreported association mode. The structure also delineates the precise arrangement of eleven core subunits and nine peripheral VCP antenna proteins, collectively forming an extensive pigment network and illuminating efficient energy transfer pathways from the antenna system to the reaction center. This study elucidates a novel PSI–FNR interaction mode and provides a structural foundation for understanding the unique supramolecular organization, efficient light harvesting, and electron transport mechanisms in N. oceanica PSI. Biological sciences/Plant sciences/Photosynthesis/Photosystem I Biological sciences/Plant sciences/Plant molecular biology Full Text Additional Declarations There is NO Competing Interest. Supplementary Files Supplementary260225.pdf Supplementary File extendedData0225.pdf Article File Cite Share Download PDF Status: Under Review 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. 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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-8964687","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":597635015,"identity":"69a3079c-87b1-4335-b860-b4bdf78b7359","order_by":0,"name":"Xiaowei 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