title: Effect of oxidized betaB3-crystallin peptide (152-166) on thermal aggregation of bovine lens gamma-crystallins: identification of peptide interacting sites.
abstract: We studied the effect of oxidized betaB3-crystallin peptide (residues 152-166) on the thermal aggregation of bovine gamma-crystallin and on chaperone activity of alpha-crystallin. Thermal aggregation of gamma-crystallin was higher in the presence of oxidized betaB3-crystallin peptide than without oxidized peptide. Increased aggregation was not observed in the presence of unoxidized betaB3-crystallin peptide or a control oxidized peptide. Enhanced aggregation of gamma-crystallin by oxidized betaB3-crystallin peptide was observed even at 37 degrees C. Interaction with oxidized betaB3-peptide increased the hydrophobicity in the gamma-crystallin as shown by increased 4, 4'-dianilino-1, 1'-binaphthyl-5, 5'-disulfonic acid (bis-ANS) binding. Enhanced aggregation of gamma-crystallin was observed despite the presence of alpha-crystallin (a chaperone protein) in the system. Sulfo succinimidyl-2-[6-(biotinamido)-2-{p-azidobenzamido}-hexanoamido]ethyl-1-3 dithio propionate (Sulfo-SBED) cross-linker studies further confirmed the interaction between oxidized betaB3-crystallin peptide and gamma-crystallin. Peptide interacted sites in gamma-crystallin were identified by matrix assisted laser desorption time-of-flight mass spectrometric methods and the result suggests that oxidized betaB3-crystallin peptide interacted with amino acid residues present on the outer surface of the gamma-crystallin. These results imply that oxidized betaB3-crystallin peptide interact with gamma-crystallins and enhance their aggregation and light scattering.
authors.affiliation: Department of Ophthalmology, EC 213, Mason Eye Institute, 1 Hospital Dr, Columbia, MO 65212, USA.
authors.forename: Padmanabha E G
authors.initials: PE
authors.lastname: Udupa
authors.forename: Krishna K
authors.initials: KK
authors.lastname: Sharma
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003459:Crystallins / Q000494:pharmacology*; D006358:Hot Temperature; D018832:Molecular Chaperones / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000494:pharmacology; D010782:Photolysis; D011485:Protein Binding; D011489:Protein Denaturation / Q000187:drug effects; D038206:beta-Crystallin B Chain; D038222:gamma-Crystallins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
chemical_list: C103908:CRYBB3 protein, human; D003459:Crystallins; D018832:Molecular Chaperones; D010446:Peptide Fragments; D038206:beta-Crystallin B Chain; D038222:gamma-Crystallins