title: The dynamic conformational landscape of gamma-secretase.
abstract: The structure and function of the gamma-secretase proteases are of great interest because of their crucial roles in cellular and disease processes. We established a novel purification protocol for the gamma-secretase complex that involves a conformation- and complex-specific nanobody, yielding highly pure and active enzyme. Using single particle electron microscopy, we analyzed the gamma-secretase structure and its conformational variability. Under steady-state conditions, the complex adopts three major conformations, which differ in overall compactness and relative position of the nicastrin ectodomain. Occupancy of the active or substrate-binding sites by inhibitors differentially stabilizes subpopulations of particles with compact conformations, whereas a mutation linked to familial Alzheimer disease results in enrichment of extended-conformation complexes with increased flexibility. Our study presents the csecretase complex as a dynamic population of interconverting conformations, involving rearrangements at the nanometer scale and a high level of structural interdependence between subunits. The fact that protease inhibition or clinical mutations, which affect amyloid beta (Abeta) generation, enrich for particular subpopulations of conformers indicates the functional relevance of the observed dynamic changes, which are likely to be instrumental for highly allosteric behavior of the enzyme.
authors.forename: Nadav
authors.initials: N
authors.lastname: Elad
authors.forename: Bart
authors.initials: B
authors.lastname: De Strooper
authors.forename: Sam
authors.initials: S
authors.lastname: Lismont
authors.forename: Wim
authors.initials: W
authors.lastname: Hagen
authors.forename: Sarah
authors.initials: S
authors.lastname: Veugelen
authors.forename: Muriel
authors.initials: M
authors.lastname: Arimon
authors.forename: Katrien
authors.initials: K
authors.lastname: Horré
authors.forename: Oksana
authors.initials: O
authors.lastname: Berezovska
authors.forename: Carsten
authors.initials: C
authors.lastname: Sachse
authors.forename: Lucía
authors.initials: L
authors.lastname: Chávez-Gutiérrez
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D020134:Catalytic Domain / Q000187:drug effects*; D002460:Cell Line; D005182:Flavin-Adenine Dinucleotide / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D007313:Insecta; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008854:Microscopy, Electron; D011487:Protein Conformation; D021122:Protein Subunits / Q000378:metabolism*
chemical_list: D008562:Membrane Glycoproteins; D021122:Protein Subunits; D005182:Flavin-Adenine Dinucleotide; D053829:Amyloid Precursor Protein Secretases