|PROSITE documentation PDOC00217|
In the photosynthetic reaction center of purple bacteria, two homologous integral membrane proteins, L(ight) and M(edium), are known to be essential to the light-mediated water-splitting process. In the photosystem II of eukaryotic chloroplasts two related proteins are involved: the D1 (psbA) and D2 proteins (psbD). These four types of protein probably evolved from a common ancestor [see 1,2 for recent reviews].
We developed a signature pattern which include two conserved histidine residues. In L and M chains, the first histidine is a ligand of the magnesium ion of the special pair bacteriochlorophyll, the second is a ligand of a ferrous non-heme iron atom. In photosystem II these two histidines are thought to play a similar role.Expert(s) to contact by email:
December 2001 / Pattern and text revised.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Michel H., Deisenhofer J.|
|Source||Trends Biochem. Sci. 12:321-326(1987).|