Purpose: To compare the spectroscopic and unfolding properties of human lens [beta]B2- and [gamma]C-crystallin with those of [alpha]A-crystallin.
Methods: Human lens [beta]B2- and [gamma]C-crystallin were cloned and measured spectroscopically. The unfolding curves in response to guanidine HCl (GdnHCl) and heat were also obtained by measuring Trp fluorescence emission intensity or emission maximum wavelength with increasing perturbation.
Results: Very similar spectroscopic and unfolding properties were seen with [beta]B2- and [gamma]C-crystallin, but both demonstrated great differences compared with [alpha]A-crystallin. Unlike [alpha]A-crystallin, [beta]B2- and [gamma]C-crystallin showed very little binding to Bis-ANS (4,4'-dianilino-1,1'-binaphthalene-5,5'-disulfonic acid), a hydrophobic fluorescence probe. Both [beta]B2- and [gamma]C-crystallin were more resistant than [alpha]A-crystallin to GdnHCl-induced unfolding, but [alpha]A-crystallin was more resistant than [beta]B2- and [gamma]C-crystallin to heat induced unfolding.
Conclusions: It was observed that [beta]B2- and [gamma]C-crystallin showed more similar spectroscopic and unfolding properties with each other than each of them showed with [alpha]A-crystallin.