Apo and Aß46-bound γ-secretase structures provide insights into amyloid-ß processing by the APH-1B isoform.
Nat Commun
; 15(1): 4479, 2024 May 27.
Article
in En
| MEDLINE
| ID: mdl-38802343
ABSTRACT
Deposition of amyloid-ß (Aß) peptides in the brain is a hallmark of Alzheimer's disease. Aßs are generated through sequential proteolysis of the amyloid precursor protein by the γ-secretase complexes (GSECs). Aß peptide length, modulated by the Presenilin (PSEN) and APH-1 subunits of GSEC, is critical for Alzheimer's pathogenesis. Despite high relevance, mechanistic understanding of the proteolysis of Aß, and its modulation by APH-1, remain incomplete. Here, we report cryo-EM structures of human GSEC (PSEN1/APH-1B) reconstituted into lipid nanodiscs in apo form and in complex with the intermediate Aß46 substrate without cross-linking. We find that three non-conserved and structurally divergent APH-1 regions establish contacts with PSEN1, and that substrate-binding induces concerted rearrangements in one of the identified PSEN1/APH-1 interfaces, providing structural basis for APH-1 allosteric-like effects. In addition, the GSEC-Aß46 structure reveals an interaction between Aß46 and loop 1PSEN1, and identifies three other H-bonding interactions that, according to functional validation, are required for substrate recognition and efficient sequential catalysis.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Amyloid beta-Peptides
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Cryoelectron Microscopy
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Amyloid Precursor Protein Secretases
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Presenilin-1
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Membrane Proteins
Limits:
Humans
Language:
En
Journal:
Nat Commun
Journal subject:
BIOLOGIA
/
CIENCIA
Year:
2024
Document type:
Article
Affiliation country:
Country of publication: