Supramolecular Nanostructure Formation of Coassembled Amyloid Inspired Peptides

Characterization
of amyloid-like aggregates through converging approaches can yield
deeper understanding of their complex self-assembly mechanisms and
the nature of their strong mechanical stability, which may in turn
contribute to the design of novel supramolecular peptide nanostructures
as functional materials. In this study, we investigated the coassembly
kinetics of oppositely charged short amyloid-inspired peptides (AIPs)
into supramolecular nanostructures by using confocal fluorescence
imaging of thioflavin T binding, turbidity assay and in situ small-angle
X-ray scattering (SAXS) analysis. We showed that coassembly kinetics
of the AIP nanostructures were consistent with nucleation-dependent
amyloid-like aggregation, and aggregation behavior of the AIPs was
affected by the initial monomer concentration and sonication. Moreover,
SAXS analysis was performed to gain structural information on the
size, shape, electron density, and internal organization of the coassembled
AIP nanostructures. The scattering data of the coassembled AIP nanostructures
were best fitted into to a combination of polydisperse core–shell
cylinder (PCSC) and decoupling flexible cylinder (FCPR) models, and
the structural parameters were estimated based on the fitting results
of the scattering data. The stability of the coassembled AIP nanostructures
in both fiber organization and bulk viscoelastic properties was also
revealed via temperature-dependent SAXS analysis and oscillatory rheology
measurements, respectively.