Age-dependent deamidation of αB-crystallin

• Published in: FEBS letters Vol. 322; no. 1; pp. 69 - 72
• Main Authors: Groenen, Patricia J.T.A., van Dongen, Maria J.P., Voorter, Christina E.M., Bloemendal, Hans, de Jong, Wilfried W.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 03.05.1993; Elsevier
• Subjects: Aged; Aged, 80 and over; Aging - metabolism; Amides - metabolism; Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Asparagine - metabolism; Biological and medical sciences; Cattle; Crystallins - metabolism; Deamidation; Fundamental and applied biological sciences. Psychology; Humans; Lens; Miscellaneous; Molecular aging; Molecular Sequence Data; Peptide Mapping; Proteins; Racemization; αB-Crystallin; Racemization; Lens; Deamidation; αB-Crystallin; Molecular aging; Proteins; Site specificity; Chemical modification; Crystallin; Correlation analysis; Beta-Peptide chain; Age
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(93)81113-E

Bovine and human αB-crystallin undergo deamidation upon aging in the lens. In bovine αB-crystallin, the specific site of dearnidation has been identified by peptide mapping after tryptic digestion. Asn-146 was found to be subject to deamidation, whereas the only other asparagine residue, at position 78, is not affected. Asn-146 is flanked at the carboxylic side by a glyeyl residue. Yet, the rate of in vivo deamidation is low. In vitro studies reveal that the deamidation is accompanied by significant racemization, indicating that the deamidation proceeds via formation of a succinimide intermediate.