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Self-Assembly and Hydrogelation of an Amyloid Peptide Fragment

DOI: 10.1021/bi8000616 DOI Help
PMID: 18370402 PMID Help

Authors: Marta J. Krysmann (University of Reading) , Valeria Castelletto (University of Reading) , Antonios .kelarakis (University of Athens) , Rohan A. Hule (University of Delaware) , Darrin J. Pochan (University of Delaware.) , Ian W. Hamley (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Biochemistry , VOL 47 (16) , PAGES 4597-4605

State: Published (Approved)
Published: April 2008

Abstract: The self-assembly of a fragment of the amyloid beta peptide that has been shown to be critical in amyloid fibrillization has been studied in aqueous solution. There are conflicting reports in the literature on the fibrillization of A beta (16-20), i.e., KLVFF, and our results shed light on this. In dilute solution, self-assembly of NH(2)-KLVFF-COOH is strongly influenced by aromatic interactions between phenylalanine units, as revealed by UV spectroscopy and circular dichroism. Fourier transform infrared (FTIR) spectroscopy reveals beta-sheet features in spectra taken for more concentrated solutions and also dried films. X-ray diffraction and cryo-transmission electron microscopy (cryo-TEM) provide further support for beta-sheet amyloid fibril formation. A comparison of cryo-TEM images with those from conventional dried and negatively stained TEM specimens highlights the pronounced effects of sample preparation on the morphology. A comparison of FTIR data for samples in solution and dried samples also highlights the strong effect of drying on the self-assembled structure. In more concentrated phosphate-buffered saline (PBS) solution, gelation of NH(2)-KLVFF-COOH is observed. This is believed to be caused by screening of the electrostatic charge on the peptide, which enables beta sheets to aggregate into a fibrillar gel network. The rheology of the hydrogel is probed, and the structure is investigated by light scattering and small-angle X-ray scattering.

Subject Areas: Chemistry, Materials

Instruments: NONE-No attached Diamond beamline

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