Reactive cysteine residues in the oxidative dimerization and Cu²⁺ induced aggregation of human γD-crystallin: Implications for age-related cataract.

ABSTRACT: Cysteine (Cys) residues are major causes of crystallin disulfide formation and aggregation in aging and cataractous human lenses. We recently found that disulfide linkages are highly and partly conserved in β- and γ-crystallins, respectively, in human age-related nuclear cataract and glutathione depleted LEGSKO mouse lenses, and could be mimicked by in vitro oxidation. Here we determined which Cys residues are involved in disulfide-mediated crosslinking of recombinant human γD-crystallin (hγD). In vitro diamide oxidation revealed dimer formation by SDS-PAGE and LC-MS analysis with Cys 111-111 and C111-C19 as intermolecular disulfides and Cys 111-109 as intramolecular sites. Mutation of Cys111 to alanine completely abolished dimerization. Addition of αB-crystallin was unable to protect Cys

SUBMITTER: Ramkumar S 

PROVIDER: S-EPMC6590075 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature