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Ascorbic acid mediated alteration of alpha-crystallin secondary structure
J E Dickerson1, M F Lou, R W Gracy
1Cataract Research Group, Alcon Laboratories, Inc., Fort Worth, TX 76134, USA.
Current Eye Research
|February 1, 1995
Summary
Ascorbic acid, a potent glycating agent, modifies alpha-crystallin structure. This study reveals ascorbate incorporation and cross-linking, impacting protein secondary structure and potentially contributing to lens aging and cataractogenesis.
Area of Science:
- Biochemistry
- Protein Chemistry
- Ophthalmology
Background:
- Glycation, a non-enzymatic protein modification, is implicated in aging and cataractogenesis.
- Alpha-crystallin is a major lens protein, crucial for maintaining lens transparency.
- Previous studies show glycation alters protein function and structure, but effects on secondary structure are debated.
Purpose of the Study:
- To investigate the effects of ascorbic acid glycation on alpha-crystallin.
- To determine if ascorbic acid induces secondary structure modifications in alpha-crystallin.
Main Methods:
- Incubation of alpha-crystallin with ascorbic acid for 1-2 weeks.
- Analysis of ascorbate incorporation and cross-linking.
- Circular dichroism (CD) spectroscopy to assess structural changes.
Main Results:
- Significant incorporation of ascorbate into alpha-crystallin was observed.
- Non-reducible cross-links formed between alpha-crystallin chains.
- Altered CD spectra in the far UV region indicated modifications to secondary structure.
Conclusions:
- Ascorbic acid is a potent glycating agent for alpha-crystallin.
- Glycation by ascorbic acid leads to secondary structure modifications in alpha-crystallin.
- These findings suggest a role for ascorbic acid-induced glycation in lens aging and cataract development.