Light-harvesting photosynthetic bile pigment-protein from the phycobiliprotein complex (phycobilisome, PBS). Phycocyanin is the major phycobiliprotein in the PBS rod. Heterodimer of an alpha and a beta subunit, which further assembles into trimers and the trimers into hexamers. Part of the phycobilisome rod. Contains one covalently linked bilin chromophore. Belongs to the phycobiliprotein family.