Low energy optical excitations as an indicator of structural changes initiated at the termini of amyloid proteins
| Autor: | Kwang Hyok Jong, Saul T. E. Jones, Amberley D. Stephens, Yavar T. Azar, Ali Hassanali, Luca Grisanti, Dan Credgington, Gabriele S. Kaminski Schierle |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
genetic structures
Amyloid General Physics and Astronomy Amyloidogenic Proteins Peptide 02 engineering and technology Protein aggregation Microscopy Atomic Force 010402 general chemistry Fibril 01 natural sciences amyloid optical properties protein aggregates excited state Microscopy Physical and Theoretical Chemistry Density Functional Theory chemistry.chemical_classification Chemistry 021001 nanoscience & nanotechnology Fluorescence eye diseases 0104 chemical sciences Spectrophotometry Biophysics Thermodynamics Density functional theory sense organs Absorption (chemistry) 0210 nano-technology |
| Zdroj: | Physical Chemistry Chemical Physics. 21:23931-23942 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/c9cp04648h |
| Popis: | There is a growing body of experimental work showing that protein aggregates associated with amyloid fibrils feature intrinsic fluorescence. In order to understand the microscopic origin of this behavior observed in non-aromatic aggregates of peptides and proteins, we conducted a combined experimental and computational study on the optical properties of amyloid-derived oligopeptides in the near-UV region. We have focused on a few model systems having charged termini (zwitterionic) or acetylated termini. For the zwitterionic system, we were able to simulate the longer tail absorption in the near UV (250-350 nm), supporting the experimental results in terms of excitation spectra. We analyzed the optical excitations responsible for the low-energy absorption and found a large role played by charge-transfer states around the termini. These charge-transfer excitations are very sensitive to the conformation of the peptide and in realistic fibrils may involve inter and intra chain charge reorganization. |
| Databáze: | OpenAIRE |
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