Isolation and crystallization of CP47, a Photosystem II chlorophyll binding protein. Degradation of CP47 upon dissociation from the core complex.

The CP47 protein was isolated from Photosystem II membranes by using a combination of the detergents n-dodecyl-beta-D-maltoside and octyl-beta-D-thioglucoside. The purified CP47 was used in a series of crystallization experiments, which yielded highly reproducible hexagonal crystals. Immunoblot analysis revealed that the isolated CP47 undergoes degradation even under dim light conditions. This degradation takes place after the protein has been dissociated from the core complex. Proteolysis experiments with trypsin demonstrated that the dissociation of the CP47 from the PS II core complex results in changes that render the protein sensitive to proteolysis.