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Updated: Jun 10, 2026
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
Summary
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.
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Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils.
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
03:03Amyloid Fibrils
Amyloid fibrils are aggregates of misfolded proteins. Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils.
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...
Amyloid deposits were observed as early as 1639 in the liver and the spleen. In 1854, Rudolph Virchow performed iodine staining, normally used to...