Abstract

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.

Details

Title
The structure of a β2-microglobulin fibril suggests a molecular basis for its amyloid polymorphism
Author
Iadanza, Matthew G 1   VIAFID ORCID Logo  ; Silvers, Robert 2   VIAFID ORCID Logo  ; Boardman, Joshua 1 ; Smith, Hugh I 1 ; Karamanos, Theodoros K 3 ; Debelouchina, Galia T 4   VIAFID ORCID Logo  ; Su, Yongchao 5   VIAFID ORCID Logo  ; Griffin, Robert G 6   VIAFID ORCID Logo  ; Ranson, Neil A 1   VIAFID ORCID Logo  ; Radford, Sheena E 1   VIAFID ORCID Logo 

 Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK 
 Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Chemistry & Biochemistry, Florida State University, Tallahassee, FL, USA 
 Astbury Centre for Structural Molecular Biology, School of Molecular & Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK; Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA 
 Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA 
 Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA; Merck Research Laboratories, Merck & Co., Inc., Kenilworth, NJ, USA 
 Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA 
Pages
1-10
Publication year
2018
Publication date
Oct 2018
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2127191903
Copyright
© 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.