Water-soluble carotenoid proteins of cyanobacteria

In photosynthetic organisms, carotenoids function in light harvesting and in photoprotection. In cyanobacteria, there have been numerous reports of proteins that bind exclusively carotenoids. Perhaps the best characterized of these proteins are the 35 kDa water-soluble orange carotenoid proteins (OCPs). Structural, biochemical, and genomic data on the OCP and its paralogs are gradually revealing how these proteins function in photoprotection.