We are studying the pigments involved in photosynthesis in cryptomonad algae. These pigments are protein-chromophore complexes, and include phycocyanins, chlorophyll c-protein and chlorophyll a-protein complexes. A particular interest is the relationship between the protein structure and spectroscopic properties of the pigments. It is a goal of this research to distinguish among three general factors involved in how a protein can perturb a chromophores spectral properties: 1. By altering the chromophores conformation; 2. By establishing interactions of the chromophores with other groups. 3. By altering the chromophores solvation. Allophycocyanin, although not a cryptomonad protein, has been used by us to demonstrate the possible importance of chromophore-chromophore interaction in a photosynthetic pigment. This interaction is dependent on the protein's quaternary structure.