Mapping amyloid-β(16-22) nucleation pathways using fluorescence lifetime imaging microscopy.
The cross-β peptide architecture is associated with numerous functional biomaterials and deleterious disease related aggregates. While these diverse and ubiquitous paracrystalline assemblies have been widely studied, a fundamental understanding of the nucleation and aggregation pathways to these structures remains elusive. Here we highlight a novel application of fluorescence lifetime imaging microscopy in characterising the critical stages of peptide aggregation. Using the central nucleating core of the amyloid-β (Aβ), Aβ(16-22), as a model cross-β system, and utilising a small fraction of rhodamine labelled peptide (Rh110-Aβ(17-22)), we map out a folding pathway from monomer to paracrystalline nanotube. Using this intrinsic fluorescence reporter, we demonstrate the effects of interfaces and evaporation on the nucleation of sub-critical concentration solutions, providing access to previously uncharacterised intermediate morphologies. Using fluorescence lifetime we follow the local peptide environment through the stages of nucleation and hydrophobic collapse, ending in a stable final structure. This work provides a metric for future implementations of measuring fluorescence lifetimes of intrinsic fluorescence reporters during the very dynamic processes relating to peptide nucleation and maturation.
Department of Physics, Emory University, Atlanta, GA, USA. neil.anthony@emory.edu.
Neil R
NR
Anthony
Anil K
AK
Mehta
David G
DG
Lynn
Keith M
KM
Berland
D016229:Amyloid beta-Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D008856:Microscopy, Fluorescence; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D058105:Polymerization; D012235:Rhodamines / Q000737:chemistry
D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; D012235:Rhodamines; C417223:amyloid beta-protein (16-22)