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Rapid Generation of Amyloid from Native Proteins In vitro
05:48

Rapid Generation of Amyloid from Native Proteins In vitro

Published on: December 5, 2013

Post-Translational Isoaspartate Promotes Amyloid Formation in β2-Microglobulin

Ryuji Kawakami1, Toshiki Takei1, Masatomo So2

  • 1Institute for Protein Research, The University of Osaka, Suita, Osaka, Japan.

Angewandte Chemie (International Ed. in English)
|June 8, 2026
PubMed

Insights

Isoaspartate modification in beta-2-microglobulin (β2m) drives amyloid formation in dialysis-related amyloidosis (DRA). This spontaneous change, particularly at Asn17, initiates protein aggregation, offering new insights into DRA pathogenesis.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Protein Chemistry

Background:

  • Dialysis-related amyloidosis (DRA) is linked to beta-2-microglobulin (β2m) aggregation.
  • The molecular triggers for β2m fibril formation are not fully understood.
  • Isoaspartate (isoAsp) formation has been proposed but not experimentally verified.

Purpose of the Study:

  • To synthesize β2m variants with isoAsp modifications at Asn17 and Asn42.
  • To investigate the role of isoAsp in β2m fibrillogenesis and DRA.
  • To provide direct experimental evidence for isoAsp-induced amyloidogenesis.

Main Methods:

  • Total chemical synthesis of β2m variants with site-specific isoAsp.
  • Structural characterization using spectroscopy and Transmission Electron Microscopy (TEM).
  • Functional assays to assess fibril formation capacity.

Main Results:

  • Successfully synthesized β2m variants with isoAsp at Asn17 and Asn42.
  • Isoaspartate at position 17 (isoAsp17) significantly enhanced β2m fibril formation.
  • isoAsp17-modified β2m showed greater aggregation propensity than the known pathogenic ΔN6-β2m variant.
  • Structural and spectroscopic data confirmed isoAsp17 promotes fibril formation.

Conclusions:

  • Provides the first direct evidence that isoaspartate modification initiates β2m amyloidogenesis.
  • Highlights isoAsp as a key molecular driver of pathological protein aggregation in DRA.
  • Redefines the molecular basis of dialysis-related amyloidosis.
Keywords:
amyloid fibril formationchemical synthesisisoaspartateβ2‐microglobulin

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