11EO

Structure of Rapidly twisting Amyloid-beta 40 fibril , RT-Ab40(C2)

Summary for 11EO

• Entry DOI: 10.2210/pdb11eo/pdb
• EMDB information: 75653
• Descriptor: RT-Ab40(C2) (1 entity in total)
• Functional Keywords: amyloid-beta 40, rapidly twisting, protein fibril, ab40
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 6
• Total formula weight: 26015.11

Authors

Larimi, M.G.,Thurber, K.R.,Tycko, R. (deposition date: 2026-02-19, release date: 2026-05-20)

Primary citation

Larimi, M.G.,Thurber, K.R.,Tycko, R.
Polymorphic structures of rapidly twisting 40-residue amyloid-beta fibrils.
Biorxiv, 2026

PubMed Abstract: Fibrils formed by 40- and 42-residue amyloid-β peptides (Aβ40 and Aβ42) are polymorphic, containing molecular structures that vary with growth conditions in ways that are not fully understood. Here we use cryogenic electron microscopy to characterize the structure of rapidly twisting Aβ40 fibrils, for which the distance between apparent width minima in electron microscope images ("cross-over distances") is approximately 25 nm. From samples grown under a single set of growth conditions, we obtain high-resolution structures for three different rapidly twisting polymorphs. Although their cross-over distances are similar, the three rapidly twisting polymorphs differ in twist handedness, symmetry, molecular conformations, and intermolecular contacts. Two of the rapidly twisting polymorphs resemble slowly twisting Aβ40 polymorphs that have been described previously, including polymorphs extracted from brain tissue of Alzheimer's disease patients or created by seeded growth from amyloid in brain tissue, but with shorter conformationally ordered segments and other specific conformational differences. These results contribute to our understanding of amyloid polymorphism, connections between morphology and molecular structure, and relationships between brain-derived and -grown fibrils.

PubMed: 42039599
DOI: 10.64898/2026.04.10.717728

Experimental method

ELECTRON MICROSCOPY (2.73 Å)