Toward Understanding Optical Properties of Amyloids: A Reaction Path and Nonadiabatic Dynamics Study
- 23 September 2020
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 142 (42), 18042-18049
- https://doi.org/10.1021/jacs.0c07134
Abstract
Amyloids have unique structural, chemical and optical properties. Although much theoretical effort has been directed toward understanding amyloid nucleation, the understanding of their optical properties has remained rather limited. In particular, the photophysical mechanisms leading to near UV excitation and characteristic blue-green luminescence in amyloid systems devoid of aromatic amino acids have not been resolved. We use ab initio static calculations and nonadiabatic dynamics simulations to study the excited electronic states of model amyloid-like peptides. We show that their photophysics is essentially governed by the multitude of nπ* states with excitation localized on the amide groups. The strong stabilization of the nπ* states with respect to the amide group deplanarization and the concomitant increase of the oscillator strength makes excitation in the near UV possible. With respect to emission, our dynamics simulations revealed that the amyloid cross β arrangement effectively hinders the nonradiative relaxation channels operative in functional proteins. Finally, we show that after relaxation of the photoexcited peptides toward the minimum of the different nπ* states, fluorescence takes place in the visible (green) part of the electromagnetic spectrum.Keywords
Funding Information
- Hrvatska Zaklada za Znanost (HRZZ IP-2016- 06-1142)
This publication has 67 references indexed in Scilit:
- Amyloid Polymorphism in the Protein Folding and Aggregation Energy LandscapeAngewandte Chemie, 2018
- Distinct thermodynamic signatures of oligomer generation in the aggregation of the amyloid-β peptideNature Chemistry, 2018
- Amyloid β Protein and Alzheimer’s Disease: When Computer Simulations Complement Experimental StudiesChemical Reviews, 2015
- Direct Observation of Heterogeneous Amyloid Fibril Growth Kinetics via Two-Color Super-Resolution MicroscopyNano Letters, 2013
- Atomic structure and hierarchical assembly of a cross-β amyloid fibrilProceedings of the National Academy of Sciences of the United States of America, 2013
- Multidimensional View of Amyloid Fibril Nucleation in Atomistic DetailJournal of the American Chemical Society, 2012
- Charge transport and intrinsic fluorescence in amyloid-like fibrilsProceedings of the National Academy of Sciences of the United States of America, 2007
- Protein Misfolding, Functional Amyloid, and Human DiseaseAnnual Review of Biochemistry, 2006
- Structure of the cross-β spine of amyloid-like fibrilsNature, 2005
- Molecular basis for amyloid fibril formation and stabilityProceedings of the National Academy of Sciences of the United States of America, 2005