AbstractThe aim of this thesis was to develop new X-ray and neutron scattering techniques to investigate amyloid fibrils. Specifically, the development of techniques which can probe kinetic and structural information that can be difficult to obtain using current techniques.
Lysozyme seeded aggregation kinetics was investigated at high concentrations and gave unexpected results for the dependence of initial elongation rate on monomer concentration. Briefly, a combined small angle and wide angle X-ray scattering technique was probed as a label-free method to follow lysozyme aggregation kinetics under shear.
A novel contrast-matched small-angle neutron scattering technique was developed which gave kinetic elongation rates for the peptide NFGAIL and the protein α-synuclein of 1.9 ± 0.1 nm min-1 and 0.66 ± 0.09 nm min-1, respectively. In addition, the technique gave a new method for estimating fibril seed lengths, which were estimated to be 91 ± 20 nm and 1900 ± 600 nm, for NFGAIL and α-synuclein, respectively. Furthermore, this technique was sensitive to secondary kinetic pathways and reported no significant contribution to the kinetics from secondary pathways.
Development of a neutron fibre diffraction technique utilising isotope-labelling allowed insight into the structural packing within TTR (105–115) fibrils. In conjunction with fibre diffraction simulations, this approach concluded the steric zipper packing within the TTR (105–115) fibrils to be that of steric zipper 3 (Parallel, face-to-face, up-down).
These techniques provided extensive information on the structure and kinetics of amyloid fibrils. The methods can be employed under physiological conditions and may be useful in the study of the prevention and inhibition of amyloid aggregation.
|Date of Award
|3 Apr 2019
|Science and Technology Facilities Council
|Adam Squires (Supervisor), Jody Mason (Supervisor) & James Doutch (Supervisor)