Megadalton-sized dityrosine aggregates of α-synuclein retain high degrees of structural disorder and internal dynamics

Preview

PDF (Preprint) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
3MB

Preview

PDF (Supplementary Material) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
1MB

Item Type:

Preprint

Title:

Megadalton-sized dityrosine aggregates of α-synuclein retain high degrees of structural disorder and internal dynamics

Creators Name:

Verzini, S. and Shah, M. and Theillet, F.X. and Belsom, A. and Bieschke, J. and Wanker, E.E. and Rappsilber, J. and Binolfi, A. and Selenko, P.

Abstract:

Heterogeneous aggregates of the human protein α-synuclein (αSyn) are abundantly found in Lewy body inclusions of Parkinson’s disease patients. While structural information on classical αSyn amyloid fibrils is available, little is known about the conformational properties of disease-relevant, non-canonical aggregates. Here, we analyze the structural and dynamic properties of megadalton-sized dityrosine adducts of αSyn that form in the presence of reactive oxygen species and cytochrome c, a proapoptotic peroxidase that is released from mitochondria during sustained oxidative stress. In contrast to canonical cross-β amyloids, these aggregates retain high degrees of internal dynamics, which enables their characterization by solution-state NMR spectroscopy. We find that intermolecular dityrosine crosslinks restrict αSyn motions only locally whereas large segments of concatenated molecules remain flexible and disordered. Indistinguishable aggregates form in crowded in vitro solutions and in complex environments of mammalian cell lysates, where relative amounts of free reactive oxygen species rather than cytochrome c are rate limiting. We further establish that dityrosine adducts inhibit classical amyloid formation by maintaining αSyn in its monomeric form and that they are non-cytotoxic despite retaining basic membrane-binding properties. Our results suggest that oxidative αSyn aggregation scavenges cytochrome c’s activity into the formation of amorphous, high molecular-weight structures that may contribute to aggregate diversity in Lewy body deposits.

Source:

bioRxiv

Publisher:

Cold Spring Harbor Laboratory Press

Article Number:

2020.07.26.202358

Date:

26 July 2020

Official Publication:

https://doi.org/10.1101/2020.07.26.202358

Related to: