InterPro domain: IPR023329

The basic structural features of the chlorophyll a-b binding protein represented in this entry include three transmembrane alpha-helices and a short amphipathic helix [ 1 ].

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 [ 2 ].

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 [ 3 ]. Both these processes are believed to mediate the distribution of excitation energy between photosystems I and II.

1. Crystal structure of spinach major light-harvesting complex at 2.72 A resolution. Nature 428, 287-92
2. 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
3. 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