Resolving the Nanoscale Structure of β-Sheet Peptide Self-Assemblies Using Single-Molecule Orientation-Localization Microscopy

Weiyan Zhou, Conor L. O’Neill, Tianben Ding, Oumeng Zhang, Jai S. Rudra, Matthew D. Lew

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Synthetic peptides that self-assemble into cross-β fibrils are versatile building blocks for engineered biomaterials due to their modularity and biocompatibility, but their structural and morphological similarities to amyloid species have been a long-standing concern for their translation. Further, their polymorphs are difficult to characterize by using spectroscopic and imaging techniques that rely on ensemble averaging to achieve high resolution. Here, we utilize Nile red (NR), an amyloidophilic fluorogenic probe, and single-molecule orientation-localization microscopy (SMOLM) to characterize fibrils formed by the designed amphipathic enantiomers KFE8L and KFE8D and the pathological amyloid-beta peptide Aβ42. Importantly, NR SMOLM reveals the helical (bilayer) ribbon structure of both KFE8 and Aβ42 and quantifies the precise tilt of the fibrils’ inner and outer backbones in relevant buffer conditions without the need for covalent labeling or sequence mutations. SMOLM also distinguishes polymorphic branched and curved morphologies of KFE8, whose backbones exhibit much more heterogeneity than those of typical straight fibrils. Thus, SMOLM is a powerful tool to interrogate the structural differences and polymorphism between engineered and pathological cross-β-rich fibrils.

Original languageEnglish
Pages (from-to)8798-8810
Number of pages13
JournalACS nano
Volume18
Issue number12
DOIs
StatePublished - Mar 26 2024

Keywords

  • fluorogenic probes
  • polymorphism
  • self-assembly
  • super-resolution microscopy
  • supramolecular helix

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