THE REACTION OF SINGLET OXYGEN WITH PROTEINS, WITH SPECIAL REFERENCE TO CRYSTALLINS

D. Balasubramanian, X. Du, J. S. Zigler

Research output: Contribution to journalArticlepeer-review

Abstract

Abstract— –Photosensitized oxidation of the eye lens proteins, the crystallins, is thought to lead to protein crosslinks and high molecular weight aggregates. Such protein modifications may be important factors in the formation of lens opacities or cataracts. We focus attention here on type 2 photo‐oxidation involving the reaction of singlet oxygen (1O2) with crystallins and some “control” proteins. We find that: (1) trp residues are oxidized to N‐formyl kynurenine and related products, but this in itself does not lead to the production of high molecular weight protein aggregates of the protein; (2) tyr residues react with 1O2 but we do not detect dihydroxyphenylalanine or bityrosine nor are protein crosslinks formed as a result; (3) oxidation of his residues appears necessary for high molecular weight protein covalent aggregates to form. Proteins devoid of his, e.g. melittin or bovine pancreatic trypsin inhibitor, do not form high molecular weight products upon reaction with 1O2. Prior reaction and blocking of his inhibits the crosslinking reactions. (4) The oxidized protein is seen to be more acidic than the parent and has an altered tertiary structure. (5) Among the crystallins, reactivity towards 1O2 varies in the order γ > β > α and also γ A/E > γ D > γ B crystallin.

Original languageEnglish (US)
Pages (from-to)761-768
Number of pages8
JournalPhotochemistry and Photobiology
Volume52
Issue number4
DOIs
StatePublished - Oct 1990

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry

Fingerprint Dive into the research topics of 'THE REACTION OF SINGLET OXYGEN WITH PROTEINS, WITH SPECIAL REFERENCE TO CRYSTALLINS'. Together they form a unique fingerprint.

Cite this