Control of the Structural Stability of alpha-Crystallin under Thermal and Chemical Stress: The Role of Carnosine

The structural properties of a-crystallin, the major protein of the eye lens of mammals, in aqueous solution are investigated by means of small angle X-ray and dynamic light scattering. The research interest is devoted in particular to the effect of carnosine in protecting the protein under stress conditions, like temperature increase and presence of denaturant (guanidinium-HCl). The results suggest that carnosine interacts, through mechanisms involving hydrophobic interactions, with a-crystallin and avoids the structural changes in the quaternary structure induced by thermal and chemical stress. It is also shown that, if mediated by carnosine, the self-aggregation of a-crystallin induced by the denaturant at higher temperature can be controlled and even partially reversed. Therefore, carnosine is effective in preserving the structural integrity of the protein, suggesting the possibility of new strategies of intervention for preventing or treating pathologies related to protein aggregation, like cataracts.