Peridinin-chlorophyll-protein, a water-soluble light-harvesting complex that has a blue-green absorbing carotenoid as its main pigment, is present in most photosynthetic dinoflagellates. These proteins are composed of two similar repeated domains. These domains constitute a scaffold with pseudo-twofold symmetry surrounding a hydrophobic cavity filled by two lipid, eight peridinin, and two chlorophyll a molecules [1].

1: Structural basis of light harvesting by carotenoids: peridinin-chlorophyll-protein from Amphidinium carterae [see comments] Hofmann E, Wrench PM, Sharples FP, Hiller RG, Welte W, Diederichs K; Science 1996;272:1788-1791. PMID:8650577