Influence of salt on the self-assembly of two model amyloid heptapeptides.
We study the effects of NaCl on the self-assembly of AAKLVFF and betaAbetaAKLVFF in solution. Both AAKLVFF and betaAbetaAKLVFF self-assemble into twisted fibers in aqueous solution. The addition of NaCl to aqueous solutions of AAKLVFF produces large crystal-like nanotapes which eventually precipitate. In contrast, highly twisted fibrils were observed for betaAbetaAKLVFF solutions at low salt concentration, while a coexistence of highly twisted fibers and nanotubes was observed for betaAbetaAKLVFF at high salt concentration. The self-assembled structures observed for betaAbetaAKLVFF in NaCl solutions were ascribed to the progressive screening of the betaAbetaAKLVFF surface charge caused by the addition of salt.
Castelletto
V
V
Department of Chemistry, The University of Reading, Reading RG6 6AD, UK. V.Castelletto@reading.ac.uk
Hamley
I W
IW
Cenker
C
C
Olsson
U
U
D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D002942:Circular Dichroism; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure; D010455:Peptides / Q000737:chemistry; D017433:Protein Structure, Secondary; D012965:Sodium Chloride / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water / Q000737:chemistry
D016229:Amyloid beta-Peptides; D010455:Peptides; D014867:Water; D012965:Sodium Chloride