Type
Text
Type
Dissertation
Advisor
London, Erwin | Smith, Steven O | Miller, Lisa | Bowen, Mark | Van Nostrand, William.
Date
2013-12-01
Keywords
Alzheimer's Disease, Amyloid, Fibrils, Inhibitors, Oligomers | Biochemistry
Department
Department of Biochemistry and Structural Biology.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76951
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
The misfolding of the 42-residue amyloid beta protein has been strongly linked to Alzheimer's Disease. Prior to forming the amyloid fibrils typically associated with Alzheimer's Disease, the amyloid beta proteins associate to form a mixture of hexameric and dodecameric oligomers. This work investigates the process by which these proteins associate into oligomers and the mechanism by which different small molecule inhibitors prevent this assembly. NMR spectroscopy, atomic force microscopy and size exclusion chromatography were employed to determine the rate at which monomers assemble into hexamers, dodecamers and fibrils, and to correlate these changes in structure with changes in toxicity to neuronal cells. It was discovered that an increase in toxicity correlated with a population shift from hexamers to dodecamers, and that various inhibitors were able to block this conversion. By use of various biophysical techniques, this work demonstrates that these inhibitors bind to the monomeric peptide and prevent association of the hexameric oligomers into higher order dodecamers, thereby arresting the formation of fibrils and blocking toxicity of the peptides. A common binding region was discovered for small molecule inhibitors such as curcumin and resveratrol. The largest changes in NMR chemical shift upon inhibitor binding to Aβ 42 involve residues at the N-terminus and within the central portion of the peptide. Similar shifts upon inhibitor binding were observed in the NMR resonances for Arg5, Ser8, Tyr10, Gln15, Lys16, Leu17 and Phe20. Measurements of water accessibility indicate that the residues that interact with inhibitors are also solvent accessible. The structural insights into the mechanism of inhibition described here provide a basis for the design of improved inhibitors that specifically target Aβ 42 dodecamers, which are emerging as the neurotoxic Aβ species. | 138 pages
Recommended Citation
Aucoin, Darryl Steven, "Assembly and Inhibition of Toxic Aβ 42 Oligomers" (2013). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2819.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2819