Structure-specific amyloid precipitation in biofluids

Nat Chem. 2022 Sep;14(9):1045-1053. doi: 10.1038/s41557-022-00976-3. Epub 2022 Jul 7.

Abstract

The composition of soluble toxic protein aggregates formed in vivo is currently unknown in neurodegenerative diseases, due to their ultra-low concentration in human biofluids and their high degree of heterogeneity. Here we report a method to capture amyloid-containing aggregates in human biofluids in an unbiased way, a process we name amyloid precipitation. We use a structure-specific chemical dimer, a Y-shaped, bio-inspired small molecule with two capture groups, for amyloid precipitation to increase affinity. Our capture molecule for amyloid precipitation (CAP-1) consists of a derivative of Pittsburgh Compound B (dimer) to target the cross β-sheets of amyloids and a biotin moiety for surface immobilization. By coupling CAP-1 to magnetic beads, we demonstrate that we can target the amyloid structure of all protein aggregates present in human cerebrospinal fluid, isolate them for analysis and then characterize them using single-molecule fluorescence imaging and mass spectrometry. Amyloid precipitation enables unbiased determination of the molecular composition and structural features of the in vivo aggregates formed in neurodegenerative diseases.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid beta-Peptides
  • Amyloid* / chemistry
  • Bodily Secretions* / chemistry
  • Humans
  • Protein Aggregates* / physiology

Substances

  • Amyloid
  • Amyloid beta-Peptides
  • Protein Aggregates