European Biophysics Journal

, 38:355

Surfactant-induced conformational transition of amyloid β-peptide

Original Paper

DOI: 10.1007/s00249-008-0379-8

Cite this article as:
Sureshbabu, N., Kirubagaran, R. & Jayakumar, R. Eur Biophys J (2009) 38: 355. doi:10.1007/s00249-008-0379-8
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Abstract

Accumulating evidence suggests that Aβ1–42–membrane interactions may play an important role in the pathogenesis of Alzheimer’s disease. However, the mechanism of this structural transition remains unknown. In this work, we have shown that submicellar concentrations of sodium dodecyl sulfate (SDS) can provide a minimal platform for Aβ1–42 self-assembly. To further investigate the relation between Aβ1–42 structure and function, we analyzed peptide conformation and aggregation at various SDS concentrations using circular dichroism (CD), Fourier transform infrared spectroscopy, and gel electrophoresis. These aggregates, as observed via atomic force microscopy, appeared as globular particles in submicellar SDS with diameters of 35–60 nm. Upon sonication, these particles increased in disc diameter to 100 nm. Pyrene I3/I1 ratios and 1-anilinonaphthalene-8-sulfonic acid binding studies indicated that the peptide interior is more hydrophobic than the SDS micelle interior. We have also used Forster resonance energy transfer between N-terminal labeled pyrene and tyrosine (10) of Aβ1–42 in various SDS concentrations for conformational analysis. The results demonstrate that SDS at submicellar concentrations accelerates the formation of spherical aggregates, which act as niduses to form large spherical aggregates upon sonication.

Keywords

Alzheimer’s disease1–42 peptideSubmicellar SDS concentrationPartially folded structuresFRET

Abbreviations

1–42

Amyloid β peptide, a 42 residue peptide

AFM

Atomic force microscopy

ANS

1-Anilinonapthalene-8-sulfonic acid ammonium salt

CD

Circular dichroism

FRET

Forster resonance energy transfer

FTIR

Fourier transformed infrared spectroscopy

SDS

Sodium dodecyl sulfate

TFA

Trifluoro acetic acid

TFE

2,2,2 Trifluoroethanol

Supplementary material

249_2008_379_MOESM1_ESM.doc (75 kb)
MOESM1 (DOC 75 kb)

Copyright information

© European Biophysical Societies' Association 2008

Authors and Affiliations

  1. 1.Bio-Organic and Neurochemistry LaboratoryCentral Leather Research InstituteChennaiIndia
  2. 2.National Institute of Ocean TechnologyChennaiIndia