title: The molecular structure and stability of the eye lens: x-ray analysis of gamma-crystallin II.
abstract: The three-dimensional structure of the eye lens protein, bovine gamma-crystallin II, has been determined at 2.6 A resolution. The protein has a tow domain beta-structure, folded into four remarkably similar 'Greed key' motifs, and shows the highest internal symmetry of any protein studied by X-ray analysis. Although the symmetrical structure seems very stable, the arrangement of the sulphydryl groups would allow intramolecular cross-linking leading to possible destabilization, and intermolecular cross-linking leading to aggregation, both of which may be important to cataract formation.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D002417:Cattle; D003459:Crystallins / Q000235:genetics; D003545:Cysteine; D005796:Genes; D007908:Lens, Crystalline / Q000378:metabolism*; D011487:Protein Conformation; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D003459:Crystallins; D003545:Cysteine