Alpha-crystallin/lens lipid interactions using resonance energy transfer.

Resonance energy transfer was used to study the interaction of alpha-crystallin with lens cortex lipid vesicles. The binding of alpha-crystallin to cortex lipid vesicles and the preincubation temperature dependence of the binding were confirmed. In this study, the tryptophan of alpha-crystallin was used as the energy donor, and the fluorescence probe N-(5-dimethylaminonaphthalene-1-sulfonyl)-1, 2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (dansyl DHPE) was chosen as the energy acceptor. Lens cortex lipid vesicles were preincorporated with dansyl DHPE. Energy transfer from the tryptophan of alpha-crystallin to dansyl DHPE was found and the energy transfer efficiency was calculated. There was a higher energy transfer efficiency between alpha-crystallin and dansyl DHPE when alpha-crystallin was preincubated at 65 degrees C compared to 22 degrees C. Data confirmed the binding of alpha-crystallin to lens cortex lipid and showed that alpha-crystallin bound more closely to the surface of cortex vesicles when it was preincubated at a higher temperature. This is probably due to the exposure of hydrophobic surfaces when alpha-crystallin is preincubated at a higher temperature.