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Self-Assembly in Aqueous solution of a Modified Amyloid Beta Peptide Fragment

DOI: 10.1016/j.bpc.2008.08.007 DOI Help

Authors: P. J. F. Harris (University of Reading) , V. Castelletto (University of Reading) , I. W. Hamley (University of Reading)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Biophysical Chemistry , VOL 139 , PAGES 29-35

State: Published (Approved)
Published: November 2008

Abstract: The self-assembly in films dried from aqueous solutions of a modified amyloid beta peptide fragment is studied. We focus on sequence A?(16–20), KLVFF, extended by two alanines at the N-terminus to give AAKLVFF. Self-assembly into twisted ribbon fibrils is observed, as confirmed by transmission electron microscopy (TEM). Dynamic light scattering reveals the semi-flexible nature of the AAKLVFF fibrils, while polarized optical microscopy shows that the peptide fibrils crystallize after an aqueous solution of AAKLVFF is matured over 5 days. The secondary structure of the fibrils is studied by FT-IR, circular dichroism and X-ray diffraction (XRD), which provide evidence for ?-sheet structure in the fibril. From high resolution TEM it is concluded that the average width of an AAKLVFF fibril is (63 ± 18) nm, indicating that these fibrils comprise beta-sheets with multiple repeats of the unit cell, determined by XRD to have b and c dimensions 1.9 and 4.4 nm with an a axis 0.96 nm, corresponding to twice the peptide backbone spacing in the antiparallel ?-sheet.

Journal Keywords: Amyloid; Peptide; Fibrils; Self-assembly

Subject Areas: Chemistry, Materials

Instruments: NONE-No attached Diamond beamline

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