The Eye Lens Protein, γS Crystallin, Undergoes Glutathionylation-Induced Disulfide Bonding Between Cysteines 22 and 26
The oxidation of cysteines in crystallins is a major age-related modification associated with cataract formation. The purpose of this research was to determine the susceptibility of γS-crystallin to glutathionylation-induced oxidation and disulfide bond formation. Recombinantly expressed wild-type h...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-03-01
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| Series: | Biomolecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2218-273X/15/3/402 |
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| Summary: | The oxidation of cysteines in crystallins is a major age-related modification associated with cataract formation. The purpose of this research was to determine the susceptibility of γS-crystallin to glutathionylation-induced oxidation and disulfide bond formation. Recombinantly expressed wild-type human γS-crystallin and four cysteine-to-serine mutants were reduced and incubated for up to 2 days with oxidized glutathione. Following incubation and alkylation, the overall degree of glutathionylation and disulfide bond formation were determined by whole-mass measurement. Tryptic digests were also analyzed by LC-MS/MS to identify specific sites of S-glutathionylation and disulfide linkages. We determined that C22, C24, and C26 undergo glutathione-mediated disulfide interchange with each other, with C24 being most susceptible to oxidation and mixed disulfide formation. Our data suggest C24 is S-glutathionylated sequentially with C22 and C26 participating in disulfide exchange reactions, yielding a major species with a single glutathionylation at C24 and a disulfide between C22 and C26. The results imply that as glutathione levels are depleted in aged lenses, γS-crystallin undergoes stepwise oxidation reactions and disulfide shuffling, which may contribute towards its aggregation and cataract formation. |
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| ISSN: | 2218-273X |