|PROSITE documentation PDOC00217
Photosynthetic reaction center proteins signature
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.
December 2001 / Pattern and text revised.
PROSITE method (with tools and information) covered by this documentation:
|REACTION_CENTER, PS00244; Photosynthetic reaction center proteins signature (PATTERN)
The first H is a magnesium ligand; The second H is a iron ligand
|Sequences known to belong to this class detected by the pattern:
||ALL, except for broad bean psbA which has Gln instead of the second His
|Other sequence(s) detected in Swiss-Prot:
|Matching PDB structures:
1AIG 1AIJ 1CLT 1DOP ... [ALL]
||Michel H., Deisenhofer J.
||Trends Biochem. Sci. 12:321-326(1987).
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