The light-harvesting complex (LHC) functions as a light receptor, it captures and delivers excitation energy to photosystems with which it is closely associated. Energy is transferred from the carotenoid and chlorophyll C (or B) to chlorophyll A and the photosynthetic reaction centers where it is used to synthesize ATP and reducing power. The LHC complex of chromophytic algae is composed of fucoxanthin, chlorophyll A and C bound non-covalently by fucoxanthin chlorophyll proteins (FCPs). The ratio of pigments in this LHC is; fucoxanthin: chlorophyll C: chlorophyll A; (0.6-1): (0.1-0.3): (1). FCPs are probably transported across the endoplasmic reticulum membranes that surround the plastid via a signal peptide, followed by translocation across the thylakoid membrane via a transit peptide. Expression is increased 5-fold under conditions of low light. Belongs to the fucoxanthin chlorophyll protein family.