Influence of the solvent on the self-assembly of a modified amyloid beta peptide fragment. I. Morphological investigation.

Full Abstract

The solvent-induced transition between self-assembled structures formed by the peptide AAKLVFF is studied via electron microscopy, light scattering, and spectroscopic techniques. The peptide is based on a core fragment of the amyloid beta-peptide, KLVFF, extended by two alanine residues. AAKLVFF exhibits distinct structures of twisted fibrils in water or nanotubes in methanol. For intermediate water/methanol compositions, these structures are disrupted and replaced by wide filamentous tapes that appear to be lateral aggregates of thin protofilaments. The orientation of the beta-strands in the twisted tapes or nanotubes can be deduced from X-ray diffraction on aligned stalks, as well as FT-IR experiments in transmission compared to attenuated total reflection. Strands are aligned perpendicular to the axis of the twisted fibrils or the nanotubes. The results are interpreted in light of recent results on the effect of competitive hydrogen bonding upon self-assembly in soft materials in water/methanol mixtures.

Author information

Author/s: Castelletto, V (V); Hamley, I W (IW); Harris, P J F (PJ); Olsson, U (U); Spencer, N (N);

Affiliation: Department of Chemistry, The University of Reading, Reading RG6 6AD, UK. V.Castelletto(-atsign-)reading.ac.uk

Journal and publication information

Publication Type: Journal Article

Journal: The journal of physical chemistry. B (J Phys Chem B), published in United States. (Language: eng)

Reference: 2009-Jul; vol 113 (issue 29) : pp 9978-87

Dates: Created 2009/07/16; Completed 2009/09/24;

PMID: 19555054, status: MEDLINE (last retrieved date: 9/24/2009)

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