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Title | Apo and Aβ46-bound γ-secretase structures provide insights into amyloid-β processing by the APH-1B isoform. |
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Journal, issue, pages | Nat Commun, Vol. 15, Issue 1, Page 4479, Year 2024 |
Publish date | May 27, 2024 |
Authors | Ivica Odorčić / Mohamed Belal Hamed / Sam Lismont / Lucía Chávez-Gutiérrez / Rouslan G Efremov / |
PubMed Abstract | Deposition of amyloid-β (Aβ) peptides in the brain is a hallmark of Alzheimer's disease. Aβs are generated through sequential proteolysis of the amyloid precursor protein by the γ-secretase ...Deposition of amyloid-β (Aβ) peptides in the brain is a hallmark of Alzheimer's disease. Aβs are generated through sequential proteolysis of the amyloid precursor protein by the γ-secretase complexes (GSECs). Aβ 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 Aβ, 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 Aβ46 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-Aβ46 structure reveals an interaction between Aβ46 and loop 1, and identifies three other H-bonding interactions that, according to functional validation, are required for substrate recognition and efficient sequential catalysis. |
External links | Nat Commun / PubMed:38802343 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.3 - 3.4 Å |
Structure data | EMDB-17112, PDB-8oqy: EMDB-17113, PDB-8oqz: |
Chemicals | ChemComp-NAG: ChemComp-PC1: |
Source |
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Keywords | MEMBRANE PROTEIN / intramembrane proteolysis / protease / di-aspartyl protease / Alzheimer's disease / complex / amyloid beta |