TY - JOUR
T1 - Photosensitized oxidation of lens crystallins
T2 - Role of conformational changes in cataract
AU - Andley, Usha
AU - Clark, Barbara
AU - Chylack, Leo T.
N1 - Funding Information:
This work is supported by the U.S. National Institutes of Health Grant R01 EY05681.
PY - 1988/2/19
Y1 - 1988/2/19
N2 - Photooxidation of lens crystallins has been found to induce significant changes in their tertiary structures, and is likely to play an important role in the crosslinking and aggregation of these proteins observed in aged and cataractous human lenses. Irradiation of calf lens α-, β-and γ-crystallins in the presence of visible light and the photosensitizers methylene blue or riboflavin and by irradiation with 300 nm radiation has been investigated. Of the three classes of crystallins, only the monomeric γ-crystallins have been found to undergo partial insolubilization in photosensitized reactions. The insoluble material is highly crosslinked by nondisulfide linkages. Moreover, change in the molecular charge of the protein is observed. Analysis of the soluble fraction of the irradiated γ-crystallin, by circular dichroism and fluorescence spectroscopy, reveals changes in the tertiary structure of the protein, probably involving a partial unfolding of the molecule. Active species of molecular oxygen play a role in these structural modifications. The change in conformation is different for each photosensitizer used, suggesting that the sensitizer-protein complexation may be important.
AB - Photooxidation of lens crystallins has been found to induce significant changes in their tertiary structures, and is likely to play an important role in the crosslinking and aggregation of these proteins observed in aged and cataractous human lenses. Irradiation of calf lens α-, β-and γ-crystallins in the presence of visible light and the photosensitizers methylene blue or riboflavin and by irradiation with 300 nm radiation has been investigated. Of the three classes of crystallins, only the monomeric γ-crystallins have been found to undergo partial insolubilization in photosensitized reactions. The insoluble material is highly crosslinked by nondisulfide linkages. Moreover, change in the molecular charge of the protein is observed. Analysis of the soluble fraction of the irradiated γ-crystallin, by circular dichroism and fluorescence spectroscopy, reveals changes in the tertiary structure of the protein, probably involving a partial unfolding of the molecule. Active species of molecular oxygen play a role in these structural modifications. The change in conformation is different for each photosensitizer used, suggesting that the sensitizer-protein complexation may be important.
UR - http://www.scopus.com/inward/record.url?scp=84958515896&partnerID=8YFLogxK
U2 - 10.1117/12.942710
DO - 10.1117/12.942710
M3 - Article
AN - SCOPUS:84958515896
SN - 0277-786X
VL - 847
SP - 187
EP - 192
JO - Proceedings of SPIE - The International Society for Optical Engineering
JF - Proceedings of SPIE - The International Society for Optical Engineering
ER -