Abstract
Abstract: :
Purpose:Heterologous, noncovalent interactions of lens crystallins are thought to play a key role in the transparent properties of the lens. We sought to measure the interaction of lens alpha and gamma crystallins during aging of the bovine lens. Methods:Alpha crystallin was immobilized on a BIAcore 3000 surface plasmon resonance sensor chip in order to obtain refractive units (RU) of gamma–II binding at equilibrium. Noncovalently attached subunits of alpha crystallin were removed using denaturing conditions (8M urea). Gamma–II (gamma B) crystallin in its native state was purified from bovine lenses of different age, and the purified protein was passed over immobilized alpha crystallin under non–denaturing conditions. Results:Higher binding was observed for gamma species purified from adult bovine lenses than from fetal lenses. The magnitude of gamma–II binding increased with increasing weight and pigmentation of the adult bovine lens. Conclusions:Our results demonstrate that under equilibrium conditions that may exist in vivo, gamma–II crystallin from the aging bovine lens shows increased noncovalent associations with alpha crystallins, consistent with the possiblilty that such interactions play an important role in the transparent properties of the aged lens.
Keywords: crystallins • chaperones • cataract