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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.

Edelman M.
Hirschberg J.

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)

Consensus pattern: [NQH]-x(4)-P-x-H-x(2)-[SAG]-x(11)-[SAGC]-x-H-[SAG](2) 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: NONE.

• Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS00244 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS00244 • Scan Swiss-Prot/TrEMBL entries against PS00244 • view ligand binding statistics

Matching PDB structures: 1AIG 1AIJ 1CLT 1DOP ... [ALL]

1	Authors	Michel H., Deisenhofer J.
	Source	Biochemistry 27:1-7(1988).

2	Authors	Barber J.
	Source	Trends Biochem. Sci. 12:321-326(1987).

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