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Assembly and Inhibition of Toxic Aβ 42 Oligomers

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dc.contributor.advisor Smith, Steven O en_US
dc.contributor.advisor Bowen, Mark en_US
dc.contributor.author Aucoin, Darryl Steven en_US
dc.contributor.other Department of Biochemistry and Structural Biology en_US
dc.date.accessioned 2017-09-20T16:51:31Z
dc.date.available 2017-09-20T16:51:31Z
dc.date.issued 2013-12-01 en_US
dc.identifier.uri http://hdl.handle.net/11401/76951 en_US
dc.description 138 pgs en_US
dc.description.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. en_US
dc.description.sponsorship This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree. en_US
dc.format Monograph en_US
dc.format.medium Electronic Resource en_US
dc.language.iso en_US en_US
dc.publisher The Graduate School, Stony Brook University: Stony Brook, NY. en_US
dc.subject.lcsh Biochemistry en_US
dc.subject.other Alzheimer's Disease, Amyloid, Fibrils, Inhibitors, Oligomers en_US
dc.title Assembly and Inhibition of Toxic Aβ 42 Oligomers en_US
dc.type Dissertation en_US
dc.mimetype Application/PDF en_US
dc.contributor.committeemember London, Erwin en_US
dc.contributor.committeemember Miller, Lisa en_US
dc.contributor.committeemember Van Nostrand, William en_US

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