Christiane Funk: Assembly and Degradation of Pigment-binding Proteins
In photosynthetic systems of cyanobacteria and plants, pigment-binding proteins are responsible for the absorption of light energy. Antenna pigments (chlorophyll and carotenoids) harvest light energy, and rapidly transfer this absorbed light energy to nearby pigments and eventually to the reaction center.
The main purpose of the proteins is to keep the pigments in their proper location and orientation, so that energy transfer is efficient and rapid. Ligation of chlorophyll to the pigment-binding proteins is a central step in the assembly of the photosynthetic apparatus. This process is complicated by the facts that a) free chlorophyll might damage the cell (photooxidative activity) in the light and b) the pigment-binding proteins are stabilized by chlorophyll, but in the absence of this pigment they are rapidly degraded. Therefore this process has to be highly coordinated, possibly by the use of special pigment-carrier proteins.