Purpose. To gain insight into the mechanism by which human α-crystallin prevents the aggregation of β and γ crystallins induced by photogenerated singlet oxygen or ultraviolet B radiation. Methods. Human α, β and γ-crystallins from young human lenses or recombinant γD and αA were exposed to singlet oxygen (1O2) generated using rose bengal and 546.8 nm radiation or to 302 nm radiation. Light scattering was measured at 400 nm. γ-Crystallins were fluorescence labeled with 2-(4′-maleimidylanilino) naphthalene-6-sulphonate (MIANS). Results. Recombinant αA prevented the 1O2-induced aggregation of recombinant γD-crystallin, but not the change in tertiary structure of γD. Addition of α to γ-MIANS increased the fluorescence intensity and anisotropy of the latter. Hill plot analysis indicated a cooperative interaction between γ-MIANS and α. UV radiation increased the aggregation of γ-MIANS as shown by an increase in fluorescence anisotropy of the bound label. α-Crystallin completely prevented this radiation-induced anisotropy increase of γ-MIANS. Conclusions. Fluorescence studies on the interaction between α-crystallin and MIANS- labeled β- and γ-crystallin should help define the chaperone-like role of α in preventing aggregation of other crystallins.
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|