Phycobilins, open-chain tetrapyrrole pigment molecules, serve as accessory photosynthetic light-harvesting pigments in red algae and cyanobacteria. Phycobilin pigments are covalently linked with proteins and formed phycobiliproteins are organized into large macromolecular complexes called phycobilisomes on the top of the thylakoid membranes. In deep water, only green light is available, thus ph...
