Self-Assembly of Cysteine into Nanofibrils Precedes Cystine Crystal Formation: Implications for Aggregation Inhibition

Damilola S. Oluwatoba, Poulami Chakraborty, Dana Laor Bar-Yosef, Miranda N. Limbach, Ehud Gazit*, Thanh D. Do*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The self-association of metabolites into well-ordered assemblies at the nanoscale has significant biological and medical implications. The thiol-containing amino acid cysteine (CYS) can assemble into amyloid-like nanofibrils, and its oxidized form, the disulfide-bonded cystine (CTE), forms hexagonal crystals as those found in cystinuria due to metabolic disorder. Yet, there have been no attempts to connect these two phenomena, especially the fibril-to-crystal transition. Here, we reveal that these are not separated events, and the CYS-forming amyloid fibrils are mechanistically linked to hexagonal CTE crystals. For the first time, we demonstrated that cysteine fibrils are a prerequisite for forming cystine crystals, as observed experimentally. To further understand this mechanism, we studied the effects of thiol-containing cystinuria drugs (tiopronin, TIO; and d-penicillamine, PEN) and the canonical epigallocatechin gallate (EGCG) amyloid inhibitor on fibril formation by CYS. The thiol-containing drugs do not solely interact with monomeric CYS via disulfide bond formation but can disrupt amyloid formation by targeting CYS oligomers. On the other hand, EGCG forms inhibitor-dominant complexes (more than one EGCG molecule per cysteine unit) to prevent CYS fibril formation. Interestingly, while CYS can be oxidized into CTE, the thiol drugs can reduce CTE back to CYS. We thus suggest that the formation of crystals in cystinuria could be halted at the initial stage by targeting CYS fibril formation as an alternative to solubilizing the water-insoluble hexagonal CTE crystals at a later stage. Taken together, we depicted a complex hierarchical organization in a simple amino acid assembly with implications for therapeutic intervention.

Original languageEnglish
Pages (from-to)32177-32187
Number of pages11
JournalACS Applied Materials and Interfaces
Volume15
Issue number27
DOIs
StatePublished - 12 Jul 2023

Funding

FundersFunder number
American Society of Mass Spectrometry Research Award
John Templeton Foundation
University of Tennessee
Department of Chemistry, University of York
Tel Aviv University

    Keywords

    • amyloid fibrils
    • cystinuria
    • hexagonal crystals
    • mass spectrometry
    • nuclear magnetic resonance
    • transmission electron spectroscopy

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