Detecting beta-amyloid aggregation from the time-resolved emission spectra

Alghamdi, A., Vyshemirsky, V. , Birch, D.J.S. and Rolinski, O.J. (2018) Detecting beta-amyloid aggregation from the time-resolved emission spectra. Methods and Applications in Fluorescence, 6(2), 024002. (doi: 10.1088/2050-6120/aa9f95) (PMID:29210673)

Abstract

Aggregation of beta-amyloids is one of key processes responsible for the development of Alzheimer's desease. Early molecular-level detection of beta-amyloid oligomers may help in early diagnosis and in the development of new intervention therapies. Our previous studies on changes in beta-amyloid's single tyrosine intrinsic fluorescence response during aggregation demonstrated a four-exponential fluorescence intensity decay, and that the ratio of the pre-exponential factors indicated the extent of aggregation in the early stages of the process before the beta-sheets are formed. Here we present a complementary approach based on time-resolved emission spectra (TRES) of amyloid's tyrosine excited at 279 nm and fluorescent in the window 240-450 nm. TRES has been used to demonstrate sturctural changes occuring on the nanosecond time scale after excitation which has significant advantages over using steady-state spectra. We demonstrate this by resolving the fluorescent species and revealing that beta-amyloid's monomers show very fast dielectric relaxation and its oligomers display a substantial spectral shift due to dielectric relaxation, which gradually decreases when oligomers become larger.

• Item Type: Articles
• Keywords: Beta-amyloid, dielectric relaxation, protein aggregation, time resolved emission spectra.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Vyshemirsky, Dr Vladislav
• Authors: Alghamdi, A., Vyshemirsky, V., Birch, D.J.S., and Rolinski, O.J.
• College/School: College of Science and Engineering > School of Mathematics and Statistics
• Journal Name: Methods and Applications in Fluorescence
• Publisher: IOP Publishing
• ISSN: 2050-6120
• ISSN (Online): 2050-6120
• Published Online: 06 December 2017
• Copyright Holders: Copyright © 2018 IOP Publishing Ltd
• First Published: First published in Methods and Applications in Fluorescence 6(2): 024002
• Publisher Policy: Reproduced in accordance with the publisher copyright policy