Recombinant amyloidogenic domain of ApoA-I: analysis of its fibrillogenic potential.
A variety of amyloid diseases are associated with fibrillar aggregates from N-terminal fragments of ApoA-I generated through a largely unexplored multi-step process. The understanding of the molecular mechanism is impaired by the lack of suitable amounts of the fibrillogenic polypeptides that could not be produced by recombinant methods so far. We report the production and the conformational analysis of recombinant ApoA-I 1-93 fragment. Similarly to the polypeptide isolated ex vivo, a pH switch from 7 to 4 induces a fast and reversible conformational transition to a helical state and leads to the identification of a key intermediate in the fibrillogenesis process. Limited proteolysis experiments suggested that the C-terminal region is involved in helix formation. The recombinant polypeptide generates fibrils at pH 4 on a time scale comparable with that of the native fragment. These findings open the way to studies on structural, thermodynamic, and kinetic aspects of ApoA-I fibrillogenesis.
Di Gaetano
Sonia
S
Istituto di Biostrutture e Bioimmagini, CNR, Napoli 80134, Italy.
Guglielmi
Fulvio
F
Arciello
Angela
A
Mangione
Palma
P
Monti
Maria
M
Pagnozzi
Daniela
D
Raimondi
Sara
S
Giorgetti
Sofia
S
Orrù
Stefania
S
Canale
Claudio
C
Pucci
Piero
P
Dobson
Christopher M
CM
Bellotti
Vittorio
V
Piccoli
Renata
R
D000682:Amyloid / Q000737:chemistry* / Q000648:ultrastructure*; D016632:Apolipoprotein A-I / Q000737:chemistry* / Q000648:ultrastructure*; D001665:Binding Sites; D019281:Dimerization; D006863:Hydrogen-Ion Concentration; D046912:Multiprotein Complexes / Q000737:chemistry / Q000648:ultrastructure; D011485:Protein Binding
D000682:Amyloid; D016632:Apolipoprotein A-I; D046912:Multiprotein Complexes