405f Protein Crystallization: Studies with Gamma D-Crystallin, a Protein Involved In Cataract Formation

Quinta Nwanosike, Athanassios Sambanis, and Ronald W. Rousseau. School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0100

Cataracts are the leading cause of blindness worldwide. At present, the only cure for cataracts is surgical removal of the lens and replacement with a plastic intraocular lens. Post-biosynthetic modifications and chemical stress of the major lens proteins, which are known as crystallins, may lead to formation of crystallin aggregates, precipitates and crystals, ultimately resulting in development of cataracts in the lens.

Gamma D-crystallin is one of the major proteins in the lens. In the present study, it has been expressed using E. coli and purified with ion exchange chromatography. Initial crystallization of this protein has been carried out in Eppendorf tubes to determine suitable concentrations for observable crystals. Further crystallization is carried out on an automated stage and with varying solution conditions.

Crystallization of a gamma D-crystallin could be predicted by measuring pre-crystallization or nucleation determinants using light scattering techniques. In this work an effort is made to correlate the crystallization habits of gamma D-crystallin and parameters observed with light scattering.