title: Identification and properties of anti-chaperone-like peptides derived from oxidized bovine lens betaL-crystallins.
abstract: Thermal aggregation of betaL-crystallin was higher in the presence of peptide fragments generated from oxidized and trypsin-digested betaL-crystallin compared with thermal aggregation of the control proteins without oxidized betaL-crystallin fragments. Increased aggregation of betaL-crystallin was also observed despite the presence of alpha-crystallin (which has anti-aggregating properties) in the system. Self-aggregation of the oxidized betaL-crystallin fragments per se was not observed under the experimental conditions. Reverse-phase HPLC analysis of the precipitate obtained after heating a mixture of betaL-crystallin and oxidized betaL-crystallin fragments revealed that more than one peptide co-precipitates with betaL-crystallin. Electrospray mass spectrometry analysis of the peptides revealed that the molecular weight(s) of the peptides ranged from 1400-1800. Tandem mass spectrometry and a data base search revealed that two of the peptides originated from betaA4-crystallin (LTIFEQENFLGR, residues 121-132) and betaB3-crystallin (AINGTWVGYEFPGYR, residues 153-167) respectively. Oxidized synthetic peptides representing the same sequence were also found to enhance the aggregation of betaL-crystallin in a manner similar to oxidized lens betaL-crystallin peptides. These data suggest that the polypeptides generated after oxidation and proteolysis of betaL-crystallins interact with denaturing proteins and facilitate their aggregation and light scattering, thus behaving like anti-chaperones.
authors.affiliation: Mason Eye Institute and the Department of Biochemistry, University of Missouri, Columbia, Missouri 65212, USA.
authors.forename: R
authors.initials: R
authors.lastname: Senthilkumar
authors.forename: Raghothama
authors.initials: R
authors.lastname: Chaerkady
authors.forename: K Krishna
authors.initials: KK
authors.lastname: Sharma
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D007908:Lens, Crystalline / Q000737:chemistry* / Q000378:metabolism; D008027:Light; D018832:Molecular Chaperones / Q000037:antagonists & inhibitors*; D008969:Molecular Sequence Data; D010100:Oxygen / Q000378:metabolism; D010455:Peptides / Q000737:chemistry*; D012542:Scattering, Radiation; D021241:Spectrometry, Mass, Electrospray Ionization; D013696:Temperature; D013997:Time Factors; D038205:beta-Crystallin A Chain / Q000737:chemistry*; D038206:beta-Crystallin B Chain / Q000737:chemistry*; D038204:beta-Crystallins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D018832:Molecular Chaperones; D010455:Peptides; D038205:beta-Crystallin A Chain; D038206:beta-Crystallin B Chain; D038204:beta-Crystallins; D010100:Oxygen