InterPro domain: IPR001344

The light-harvesting complex (LHC) consists of chlorophylls A and B and the chlorophyll A-B binding protein. LHC functions as a light receptor that captures and delivers excitation energy to photosystems I and II with which it is closely associated. Under changing light conditions, the reversible phosphorylation of light harvesting chlorophyll a/b binding proteins (LHCII) represents a system for balancing the excitation energy between the two photosystems [ 1 ].

The N terminus of the chlorophyll A-B binding protein extends into the stroma where it is involved with adhesion of granal membranes and photo-regulated by reversible phosphorylation of its threonine residues [ 2 ]. Both these processes are believed to mediate the distribution of excitation energy between photosystems I and II.

This family also includes the photosystem II protein PsbS, which plays a role in energy-dependent quenching that increases thermal dissipation of excess absorbed light energy in the photosystem [ 3 ].

This entry is limited to plant and chromista proteins.

1. NaCl-induced phosphorylation of light harvesting chlorophyll a/b proteins in thylakoid membranes from the halotolerant green alga, Dunaliella salina. FEBS Lett. 569, 337-40
2. The N-terminal domain of the light-harvesting chlorophyll a/b-binding protein complex (LHCII) is essential for its acclimative proteolysis. FEBS Lett. 466, 385-8
3. Regulation of photosynthetic light harvesting involves intrathylakoid lumen pH sensing by the PsbS protein. J. Biol. Chem. 279, 22866-74