Browsing by Subject "Electron cryo-microscopy"

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    Cryo-EM structures of amyloid-β filaments with the Arctic mutation (E22G) from human and mouse brains
    (Springer, 2023) Yang, Yang; Zhang, Wenjuan; Murzin, Alexey G.; Schweighauser, Manuel; Huang, Melissa; Lövestam, Sofia; Peak‑Chew, Sew Y.; Saito, Takashi; Saido, Takaomi C.; Macdonald, Jennifer; Lavenir, Isabelle; Ghetti, Bernardino; Graff, Caroline; Kumar, Amit; Nordberg, Agneta; Goedert, Michel; Scheres, Sjors H. W.; Pathology and Laboratory Medicine, School of Medicine
    The Arctic mutation, encoding E693G in the amyloid precursor protein (APP) gene [E22G in amyloid-β (Aβ)], causes dominantly inherited Alzheimer’s disease. Here, we report the high-resolution cryo-EM structures of Aβ filaments from the frontal cortex of a previously described case (AβPParc1) with the Arctic mutation. Most filaments consist of two pairs of non-identical protofilaments that comprise residues V12–V40 (human Arctic fold A) and E11–G37 (human Arctic fold B). They have a substructure (residues F20–G37) in common with the folds of type I and type II Aβ42. When compared to the structures of wild-type Aβ42 filaments, there are subtle conformational changes in the human Arctic folds, because of the lack of a side chain at G22, which may strengthen hydrogen bonding between mutant Aβ molecules and promote filament formation. A minority of Aβ42 filaments of type II was also present, as were tau paired helical filaments. In addition, we report the cryo-EM structures of Aβ filaments with the Arctic mutation from mouse knock-in line AppNL−G−F. Most filaments are made of two identical mutant protofilaments that extend from D1 to G37 (AppNL−G−F murine Arctic fold). In a minority of filaments, two dimeric folds pack against each other in an anti-parallel fashion. The AppNL−G−F murine Arctic fold differs from the human Arctic folds, but shares some substructure.
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    Cryo-EM structures of Aβ40 filaments from the leptomeninges of individuals with Alzheimer’s disease and cerebral amyloid angiopathy
    (Springer Nature, 2023-12-04) Yang, Yang; Murzin, Alexey G.; Peak-Chew, Sew; Franco, Catarina; Garringer, Holly J.; Newell, Kathy L.; Ghetti, Bernardino; Goedert, Michel; Scheres, Sjors H. W.; Pathology and Laboratory Medicine, School of Medicine
    We used electron cryo-microscopy (cryo-EM) to determine the structures of Aβ40 filaments from the leptomeninges of individuals with Alzheimer's disease and cerebral amyloid angiopathy. In agreement with previously reported structures, which were solved to a resolution of 4.4 Å, we found three types of filaments. However, our new structures, solved to a resolution of 2.4 Å, revealed differences in the sequence assignment that redefine the fold of Aβ40 peptides and their interactions. Filaments are made of pairs of protofilaments, the ordered core of which comprises D1-G38. The different filament types comprise one, two or three protofilament pairs. In each pair, residues H14-G37 of both protofilaments adopt an extended conformation and pack against each other in an anti-parallel fashion, held together by hydrophobic interactions and hydrogen bonds between main chains and side chains. Residues D1-H13 fold back on the adjacent parts of their own chains through both polar and non-polar interactions. There are also several additional densities of unknown identity. Sarkosyl extraction and aqueous extraction gave the same structures. By cryo-EM, parenchymal deposits of Aβ42 and blood vessel deposits of Aβ40 have distinct structures, supporting the view that Alzheimer's disease and cerebral amyloid angiopathy are different Aβ proteinopathies.
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    Cryo-EM structures of tau filaments from Alzheimer’s disease with PET ligand APN-1607
    (Springer, 2021-05) Shi, Yang; Murzin, Alexey G.; Falcon, Benjamin; Epstein, Alexander; Machin, Jonathan; Tempest, Paul; Newell, Kathy L.; Vidal, Ruben; Garringer, Holly J.; Sahara, Naruhiko; Higuchi, Makoto; Ghetti, Bernardino; Jang, Ming‑Kuei; Scheres, Sjors H. W.; Goedert, Michel; Pathology and Laboratory Medicine, School of Medicine
    Tau and Aβ assemblies of Alzheimer's disease (AD) can be visualized in living subjects using positron emission tomography (PET). Tau assemblies comprise paired helical and straight filaments (PHFs and SFs). APN-1607 (PM-PBB3) is a recently described PET ligand for AD and other tau proteinopathies. Since it is not known where in the tau folds PET ligands bind, we used electron cryo-microscopy (cryo-EM) to determine the binding sites of APN-1607 in the Alzheimer fold. We identified two major sites in the β-helix of PHFs and SFs and a third major site in the C-shaped cavity of SFs. In addition, we report that tau filaments from posterior cortical atrophy (PCA) and primary age-related tauopathy (PART) are identical to those from AD. In support, fluorescence labelling showed binding of APN-1607 to intraneuronal inclusions in AD, PART and PCA. Knowledge of the binding modes of APN-1607 to tau filaments may lead to the development of new ligands with increased specificity and binding activity. We show that cryo-EM can be used to identify the binding sites of small molecules in amyloid filaments.
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    Mutation ∆K281 in MAPT causes Pick’s disease
    (Springer, 2023) Schweighauser, Manuel; Garringer, Holly J.; Klingstedt, Therése; Nilsson, K. Peter R.; Masuda‑Suzukake, Masami; Murrell, Jill R.; Risacher, Shannon L.; Vidal, Ruben; Scheres, Sjors H. W.; Goedert, Michel; Ghetti, Bernardino; Newell, Kathy L.; Pathology and Laboratory Medicine, School of Medicine
    Two siblings with deletion mutation ∆K281 in MAPT developed frontotemporal dementia. At autopsy, numerous inclusions of hyperphosphorylated 3R Tau were present in neurons and glial cells of neocortex and some subcortical regions, including hippocampus, caudate/putamen and globus pallidus. The inclusions were argyrophilic with Bodian silver, but not with Gallyas-Braak silver. They were not labelled by an antibody specific for tau phosphorylated at S262 and/or S356. The inclusions were stained by luminescent conjugated oligothiophene HS-84, but not by bTVBT4. Electron cryo-microscopy revealed that the core of tau filaments was made of residues K254-F378 of 3R Tau and was indistinguishable from that of Pick's disease. We conclude that MAPT mutation ∆K281 causes Pick's disease.
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    Tau filaments from multiple cases of sporadic and inherited Alzheimer's disease adopt a common fold
    (Springer, 2018-11) Falcon, Benjamin; Zhang, Wenjuan; Schweighauser, Manuel; Murzin, Alexey G.; Vidal, Ruben; Garringer, Holly J.; Ghetti, Bernardino; Scheres, Sjors H. W.; Goedert, Michel; Pathology and Laboratory Medicine, School of Medicine
    The ordered assembly of tau protein into abnormal filaments is a defining characteristic of Alzheimer's disease (AD) and other neurodegenerative disorders. It is not known if the structures of tau filaments vary within, or between, the brains of individuals with AD. We used a combination of electron cryo-microscopy (cryo-EM) and immuno-gold negative-stain electron microscopy (immuno-EM) to determine the structures of paired helical filaments (PHFs) and straight filaments (SFs) from the frontal cortex of 17 cases of AD (15 sporadic and 2 inherited) and 2 cases of atypical AD (posterior cortical atrophy). The high-resolution structures of PHFs and SFs from the frontal cortex of 3 cases of AD, 2 sporadic and 1 inherited, were determined by cryo-EM. We also used immuno-EM to study the PHFs and SFs from a number of cortical and subcortical brain regions. PHFs outnumbered SFs in all AD cases. By cryo-EM, PHFs and SFs were made of two C-shaped protofilaments with a combined cross-β/β-helix structure, as described previously for one case of AD. The higher resolution structures obtained here showed two additional amino acids at each end of the protofilament. The immuno-EM findings, which indicated the presence of repeats 3 and 4, but not of the N-terminal regions of repeats 1 and 2, of tau in the filament cores of all AD cases, were consistent with the cryo-EM results. These findings show that there is no significant variation in tau filament structures between individuals with AD. This knowledge will be crucial for understanding the mechanisms that underlie tau filament formation and for developing novel diagnostics and therapies.