UniProt functional annotation for P32422



	UniProt functional annotation for P32422

UniProt code: P32422.

Organism: Synechocystis sp. (strain PCC 6803 / Kazusa).

Taxonomy: Bacteria; Cyanobacteria; Synechococcales; Merismopediaceae; Synechocystis; unclassified Synechocystis.

Function: Apoprotein for the two 4Fe-4S centers FA and FB of photosystem I (PSI); essential for photochemical activity. FB is the terminal electron acceptor of PSI, donating electrons to ferredoxin. The C-terminus interacts with PsaA/B/D and helps assemble the protein into the PSI complex. Required for binding of PsaD and PsaE to PSI. PSI is a plastocyanin/cytochrome c6-ferredoxin oxidoreductase, converting photonic excitation into a charge separation, which transfers an electron from the donor P700 chlorophyll pair to the spectroscopically characterized acceptors A0, A1, FX, FA and FB in turn. {ECO:0000255|HAMAP-Rule:MF_01303, ECO:0000269|PubMed:7579183}.

Function: Mutant proteins with a 3Fe-4S center are unable to reconstitute PSI activity in vivo. {ECO:0000269|PubMed:7579183}.

Catalytic activity: Reaction=hnu + oxidized [2Fe-2S]-[ferredoxin] + reduced [plastocyanin] = oxidized [plastocyanin] + reduced [2Fe-2S]-[ferredoxin]; Xref=Rhea:RHEA:30407, Rhea:RHEA-COMP:10000, Rhea:RHEA-COMP:10001, Rhea:RHEA-COMP:10039, Rhea:RHEA-COMP:10040, ChEBI:CHEBI:29036, ChEBI:CHEBI:30212, ChEBI:CHEBI:33737, ChEBI:CHEBI:33738, ChEBI:CHEBI:49552; EC=1.97.1.12; Evidence={ECO:0000255|HAMAP- Rule:MF_01303};

Cofactor: Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883; Note=Binds 2 [4Fe-4S] clusters. Cluster 2 is most probably the spectroscopically characterized electron acceptor FA and cluster 1 is most probably FB.;

Subunit: The cyanobacterial PSI reaction center is composed of one copy each of PsaA,B,C,D,E,F,I,J,K,L,M and X, and forms trimeric complexes.

Subcellular location: Cellular thylakoid membrane; Peripheral membrane protein; Cytoplasmic side.

Annotations taken from UniProtKB at the EBI.


Organism:		Synechocystis sp. (strain PCC 6803 / Kazusa).
Taxonomy:		Bacteria; Cyanobacteria; Synechococcales; Merismopediaceae; Synechocystis; unclassified Synechocystis.



Function:		Apoprotein for the two 4Fe-4S centers FA and FB of photosystem I (PSI); essential for photochemical activity. FB is the terminal electron acceptor of PSI, donating electrons to ferredoxin. The C-terminus interacts with PsaA/B/D and helps assemble the protein into the PSI complex. Required for binding of PsaD and PsaE to PSI. PSI is a plastocyanin/cytochrome c6-ferredoxin oxidoreductase, converting photonic excitation into a charge separation, which transfers an electron from the donor P700 chlorophyll pair to the spectroscopically characterized acceptors A0, A1, FX, FA and FB in turn. {ECO:0000255\|HAMAP-Rule:MF_01303, ECO:0000269\|PubMed:7579183}.



Function:		Mutant proteins with a 3Fe-4S center are unable to reconstitute PSI activity in vivo. {ECO:0000269\|PubMed:7579183}.


Catalytic activity:		Reaction=hnu + oxidized [2Fe-2S]-[ferredoxin] + reduced [plastocyanin] = oxidized [plastocyanin] + reduced [2Fe-2S]-[ferredoxin]; Xref=Rhea:RHEA:30407, Rhea:RHEA-COMP:10000, Rhea:RHEA-COMP:10001, Rhea:RHEA-COMP:10039, Rhea:RHEA-COMP:10040, ChEBI:CHEBI:29036, ChEBI:CHEBI:30212, ChEBI:CHEBI:33737, ChEBI:CHEBI:33738, ChEBI:CHEBI:49552; EC=1.97.1.12; Evidence={ECO:0000255\|HAMAP- Rule:MF_01303};
Cofactor:		Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883; Note=Binds 2 [4Fe-4S] clusters. Cluster 2 is most probably the spectroscopically characterized electron acceptor FA and cluster 1 is most probably FB.;
Subunit:		The cyanobacterial PSI reaction center is composed of one copy each of PsaA,B,C,D,E,F,I,J,K,L,M and X, and forms trimeric complexes.
Subcellular location:		Cellular thylakoid membrane; Peripheral membrane protein; Cytoplasmic side.