{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T17:17:20Z","timestamp":1790270240246,"version":"4.1.0"},"posted":{"date-parts":[[2026,4,27]]},"group-title":"Biophysics","reference-count":44,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,4,27]],"date-time":"2026-04-27T00:00:00Z","timestamp":1777248000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"award":["AI171110"],"award-info":[{"award-number":["AI171110"]}],"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}]},{"award":["GM145238"],"award-info":[{"award-number":["GM145238"]}],"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}]},{"award":["GM124169"],"award-info":[{"award-number":["GM124169"]}],"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,9,21]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:p>The SARS CoV 2 accessory protein Orf9b is in a complex monomer-dimer equilibrium that influences its interactions with the host mitochondrial receptor Tom70. This interaction is critical for viral suppression of a Type-1 interferon response during infection. Modulating this equilibrium with a small molecule, either by stabilizing the Orf9b homodimer or blocking its interaction with Tom70, represents a promising strategy for restoring interferon signaling and the antiviral response. To build tool molecules that could test this concept, we performed two screens: a crystallographic fragment screen against the Orf9b homodimer and a high-throughput fluorescence polarization screen for competitors of an Orf9b-derived peptide binding to Tom70. Fragment screening revealed two binding sites with potential to be developed into an inhibitor: one located at the peripheral dimer interface and the other just outside the lipid-binding channel that defines the central dimer interface. Functionalization of the fragments outside of the lipid-binding channel with hydrophobic moieties stabilized the Orf9b homodimer thereby indirectly inhibiting association with Tom70. In parallel, the high throughput screen for competitive inhibitors of the Tom70:Orf9b interaction discovered a separate series of molecules. These molecules display dynamic structure activity relationship (SAR) and could be improved in the future to modulate the interaction between Tom70 and potentially a wide range of substrates. Collectively, these results demonstrate the feasibility of two distinct strategies to manipulate the Orf9b-Tom70 equilibrium, which is critical to the host response to SARS CoV 2 infection.<\/jats:p>","DOI":"10.64898\/2026.04.27.721040","type":"posted-content","created":{"date-parts":[[2026,4,27]],"date-time":"2026-04-27T22:15:50Z","timestamp":1777328150000},"source":"Crossref","is-referenced-by-count":0,"title":["Inhibiting the interaction between the mitochondrial receptor Tom70 and SARS CoV 2 Orf9b with small molecules"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2695-5951","authenticated-orcid":false,"given":"CJ San","family":"Felipe","sequence":"first","affiliation":[{"name":"Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2238-8590","authenticated-orcid":false,"given":"Kliment A","family":"Verba","sequence":"additional","affiliation":[{"name":"Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4902-337X","authenticated-orcid":false,"given":"Nevan J","family":"Krogan","sequence":"additional","affiliation":[{"name":"Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States"},{"name":"Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3509-5997","authenticated-orcid":false,"given":"Michael","family":"Grabe","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Chemistry and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5080-2859","authenticated-orcid":false,"given":"James S","family":"Fraser","sequence":"additional","affiliation":[{"name":"Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, United States"},{"name":"Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026092409550674000_2026.04.27.721040v2.1","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1016\/j.str.2025.11.011","article-title":"An Allosteric Network Governs Tom70 Conformational Dynamics to Coordinate Mitochondrial Import","volume":"34","year":"2026","journal-title":"Structure"},{"issue":"1","key":"2026092409550674000_2026.04.27.721040v2.2","doi-asserted-by":"crossref","first-page":"108936","DOI":"10.1016\/j.celrep.2021.108936","article-title":"The Chaperone-Binding Activity of the Mitochondrial Surface Receptor Tom70 Protects the Cytosol against Mitoprotein-Induced Stress","volume":"35","year":"2021","journal-title":"Cell Reports"},{"key":"2026092409550674000_2026.04.27.721040v2.3","doi-asserted-by":"publisher","DOI":"10.1083\/jcb.201708044"},{"issue":"5","key":"2026092409550674000_2026.04.27.721040v2.4","first-page":"621","article-title":"\u201cFragment-Based Identification of Druggable \u2018Hot Spots\u2019 of Proteins Using Fourier Domain Correlation Techniques.\u201d Bioinformatics (Oxford","volume":"25","year":"2009","journal-title":"England"},{"key":"2026092409550674000_2026.04.27.721040v2.5","doi-asserted-by":"publisher","DOI":"10.1016\/bs.mie.2018.09.027"},{"key":"2026092409550674000_2026.04.27.721040v2.6","doi-asserted-by":"publisher","DOI":"10.1126\/sciadv.adt7836"},{"key":"2026092409550674000_2026.04.27.721040v2.7","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.96.21.11752"},{"key":"2026092409550674000_2026.04.27.721040v2.8","doi-asserted-by":"publisher","DOI":"10.1101\/2024.10.10.615955"},{"issue":"Pt 4","key":"2026092409550674000_2026.04.27.721040v2.9","first-page":"486","article-title":"\u201cFeatures and Development of Coot.\u201d Acta Crystallographica. 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