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 (PubMed:103794). Heterodimers further assemble into trimers and the trimers into hexamers (By similarity). Part of the phycobilisome rod. Contains one covalently linked phycocyanobilin chromophore. Belongs to the phycobiliprotein family.