Specific racemization and isomerization of the aspartyl residue of αA- crystallin due to UV-B irradiation

Noriko Fujii, Yuko Momose, Yoshihiro Ishibashi, Toshimasa Uemura, Masatoshi Takita, Makoto Takehana

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38 Citations (Scopus)

Abstract

We have reported that the aspartyl (Asp)-151 residue in αA-crystallin in human eye lens was inverted to the D-isomer and isomerized to β-Asp residue with age. We report here that ultraviolet (UV)-B irradiation induces the racemization and isomerization of the Asp-151 residue of αA-crystallin from lenses of 6-week-old rats to form D-isomer and β-Asp residue. Simultaneous racemization and isomerization of the specific Asp residue indicate that the reaction proceeds via formation of a succinimide intermediate. This modification was not observed in UV-A irradiated and normal lenses. UV-B irradiation induced the racemination of only the Asp-151 residue and did not affect the other Asp residues in αA-crystallin. On the other hand, the high molecular weight fraction of the lens protein increased upon UV-B irradiation. Modification of the Asp residue would affect the three-dimensional packing array of the lens protein.

Original languageEnglish
Pages (from-to)99-104
Number of pages6
JournalExperimental Eye Research
Volume65
Issue number1
DOIs
Publication statusPublished - 1997 Jul

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Keywords

  • αA-Crystallin
  • β-Aspartic acid
  • D-Aspartic acid
  • Isomerization
  • Lens
  • Racemization
  • Ultraviolet irradiation

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems

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