title: Quantification of anti-aggregation activity of UV-irradiated α-crystallin.
abstract: Ultraviolet radiation is a risk factor for cataractogenesis. It is believed that enhanced rates of lens opacification and cataract formation are the results of gradual loss of chaperone-like efficiency of α-crystallin upon exposure to UV light. To characterize chaperone-like activity of α-crystallin damaged by UV irradiation, a test system based on dithiothreitol-induced aggregation of holo-α-lactalbumin from bovine milk was used. The adsorption capacity of α-crystallin (AC0) with respect to the target protein (α-lactalbumin) was used as a measure of anti-aggregation activity of α-crystallin. The data on SDS-PAGE testify that UV irradiation of α-crystallin results in covalent cross-linking of subunits in α-crystallin oligomers. The dependence of AC0 value on the irradiation dose was compared with the UV-induced diminution of the portion of native α-crystallin estimated from the data on differential scanning calorimetry. On the basis of such comparison a conclusion has been made that the loss in chaperone-like activity is mainly due to UV-induced denaturation of α-crystallin subunits. Cross-linking of remaining native subunits leads to an additional decrease in anti-aggregation activity.
authors.affiliation: Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow 119071, Russia.
authors.forename: Vera A
authors.initials: VA
authors.lastname: Borzova
authors.affiliation: Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow 119071, Russia.
authors.forename: Kira A
authors.initials: KA
authors.lastname: Markossian
authors.affiliation: Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin str. 4, Moscow 119991, Russia.
authors.forename: Konstantin O
authors.initials: KO
authors.lastname: Muranov
authors.affiliation: Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin str. 4, Moscow 119991, Russia.
authors.forename: Nikolay B
authors.initials: NB
authors.lastname: Polyansky
authors.affiliation: Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow 119071, Russia.
authors.forename: Sergey Yu
authors.initials: SY
authors.lastname: Kleymenov
authors.affiliation: Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow 119071, Russia. Electronic address: kurganov@inbi.ras.ru.
authors.forename: Boris I
authors.initials: BI
authors.lastname: Kurganov
mesh_terms: D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D004229:Dithiothreitol / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D007768:Lactalbumin / Q000737:chemistry; D066263:Protein Aggregation, Pathological / Q000188:drug therapy*; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D014466:Ultraviolet Rays; D038201:alpha-Crystallins / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D038201:alpha-Crystallins; D007768:Lactalbumin; D004229:Dithiothreitol
keywords: Chaperone-like activity; Cross-linking; UV irradiation; α-Crystallin