{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T03:50:30Z","timestamp":1792122630840,"version":"4.4.0"},"reference-count":51,"publisher":"National Academy of Sciences","issue":"28","license":[{"start":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T00:00:00Z","timestamp":1783468800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000049","name":"HHS | NIH | National Institute on Aging","doi-asserted-by":"publisher","award":["AG058504"],"award-info":[{"award-number":["AG058504"]}],"id":[{"id":"10.13039\/100000049","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000057","name":"HHS | NIH | National Institute of General Medical Sciences","doi-asserted-by":"publisher","award":["GM132997"],"award-info":[{"award-number":["GM132997"]}],"id":[{"id":"10.13039\/100000057","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004359","name":"Swedish Research Council","doi-asserted-by":"crossref","award":["VR2015-00143"],"award-info":[{"award-number":["VR2015-00143"]}],"id":[{"id":"10.13039\/501100004359","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[2026,7,14]]},"abstract":"<jats:p>\n                    Amyloid-\u03b2 (A\u03b2) fibrils primarily composed of A\u03b2\n                    <jats:sub>1-40<\/jats:sub>\n                    and A\u03b2\n                    <jats:sub>1-42<\/jats:sub>\n                    form the core of senile plaques in Alzheimer\u2019s disease. A\u03b2\n                    <jats:sub>1-40<\/jats:sub>\n                    fibrils may exhibit significant polymorphism influenced by sample preparation conditions, complicating atomic resolution structural characterization. To establish a reliable structural baseline, we developed a protocol for expressing and purifying recombinant A\u03b2\n                    <jats:sub>1-40<\/jats:sub>\n                    that forms monomorphic fibrils under physiological conditions (pH 7.4). We present a high-resolution structure of these unseeded, monomorphic A\u03b2\n                    <jats:sub>1-40<\/jats:sub>\n                    fibrils obtained using magic-angle spinning NMR spectroscopy (PDB ID 12GB). We obtained unambiguous chemical shift assignments for approximately 90% of the residues and measured over 500 distance and torsion angle restraints. The resolved structure, with a backbone RMSD of 0.63 \u00b1 0.06 \u00c5, shows two monomers per filament plane, with two distinct \u03b2-sheets (residues E11-E22 and K28-V39, respectively) running along the fibril axis with H-bonding between each plane, and the two strands linked by a flexible loop region. This structure reveals three continuous hydrophobic cores inside each filament which bury 24 hydrophobic side chains per filament plane: those of L17, F19, A21, V24, A30, I32, M35, V40 between the two \u03b2-strands within each monomer and I31, L34, V36, V39 between the two monomers. Small angle X-ray scattering reveals the size and geometry of the fibril cross-section, which is compatible with a two-filament arrangement with a total of 4 monomers per fibril plane.\n                  <\/jats:p>","DOI":"10.1073\/pnas.2603575123","type":"journal-article","created":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T17:38:23Z","timestamp":1783532303000},"update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":1,"title":["High-resolution structure of monomorphic A\u03b2\n                    <sub>1-40<\/sub>\n                    fibrils"],"prefix":"10.1073","volume":"123","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3272-5028","authenticated-orcid":false,"given":"Salima","family":"Bahri","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/042nb2s44","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of 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University","place":["Tallahassee"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-6839-2510","authenticated-orcid":false,"given":"Brian","family":"Michael","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/042nb2s44","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology","place":["Cambridge"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7779-9680","authenticated-orcid":false,"given":"Veronica","family":"Lattanzi","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/012a77v79","id-type":"ROR","asserted-by":"publisher"}],"name":"Biochemistry and Structural Biology, Department of Chemistry, Lund University","place":["Lund, 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