6GK3 image
Deposition Date 2018-05-18
Release Date 2018-11-14
Last Version Date 2024-10-23
Entry Detail
PDB ID:
6GK3
Keywords:
Title:
Two protofilament beta-2-microglobulin amyloid fibril
Biological Source:
Source Organism:
Homo sapiens (Taxon ID: 9606)
Host Organism:
Method Details:
Experimental Method:
Resolution:
3.98 Å
Aggregation State:
FILAMENT
Reconstruction Method:
HELICAL
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Beta-2-microglobulin
Gene (Uniprot):B2M
Chain IDs:A, B, C, D, E, F, G, H
Chain Length:64
Number of Molecules:8
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
The structure of a beta2-microglobulin fibril suggests a molecular basis for its amyloid polymorphism.
Nat Commun 9 4517 4517 (2018)
PMID: 30375379 DOI: 10.1038/s41467-018-06761-6

Abstact

All amyloid fibrils contain a cross-β fold. How this structure differs in fibrils formed from proteins associated with different diseases remains unclear. Here, we combine cryo-EM and MAS-NMR to determine the structure of an amyloid fibril formed in vitro from β2-microglobulin (β2m), the culprit protein of dialysis-related amyloidosis. The fibril is composed of two identical protofilaments assembled from subunits that do not share β2m's native tertiary fold, but are formed from similar β-strands. The fibrils share motifs with other amyloid fibrils, but also contain unique features including π-stacking interactions perpendicular to the fibril axis and an intramolecular disulfide that stabilises the subunit fold. We also describe a structural model for a second fibril morphology and show that it is built from the same subunit fold. The results provide insights into the mechanisms of fibril formation and the commonalities and differences within the amyloid fold in different protein sequences.

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Primary Citation of related structures