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Protein

Photosystem I iron-sulfur center

Gene

psaC

Organism
Synechococcus sp. (strain ATCC 27264 / PCC 7002 / PR-6) (Agmenellum quadruplicatum)
Status
Reviewed-Annotation score: -Experimental evidence at protein leveli

Functioni

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.
Mutant proteins with a 3Fe-4S center are not observed bound to PSI in vitro, and are probably not able to do so in vivo.

Catalytic activityi

Reduced plastocyanin + oxidized ferredoxin + light = oxidized plastocyanin + reduced ferredoxin.

Cofactori

[4Fe-4S] clusterNote: Binds 2 [4Fe-4S] clusters. Cluster 2 is most probably the spectroscopically characterized electron acceptor FA and cluster 1 is most probably FB.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Metal bindingi11Iron-sulfur 1 (4Fe-4S)1
Metal bindingi14Iron-sulfur 1 (4Fe-4S)1
Metal bindingi17Iron-sulfur 1 (4Fe-4S)1
Metal bindingi21Iron-sulfur 2 (4Fe-4S)1
Metal bindingi48Iron-sulfur 2 (4Fe-4S)1
Metal bindingi51Iron-sulfur 2 (4Fe-4S)1
Metal bindingi54Iron-sulfur 2 (4Fe-4S)1
Metal bindingi58Iron-sulfur 1 (4Fe-4S)1

GO - Molecular functioni

GO - Biological processi

Keywordsi

Molecular functionOxidoreductase
Biological processElectron transport, Photosynthesis, Transport
Ligand4Fe-4S, Iron, Iron-sulfur, Metal-binding

Names & Taxonomyi

Protein namesi
Recommended name:
Photosystem I iron-sulfur center (EC:1.97.1.12)
Alternative name(s):
9 kDa polypeptide
PSI-C
Photosystem I subunit VII
PsaC
Gene namesi
Name:psaC
Ordered Locus Names:SYNPCC7002_A1589
OrganismiSynechococcus sp. (strain ATCC 27264 / PCC 7002 / PR-6) (Agmenellum quadruplicatum)
Taxonomic identifieri32049 [NCBI]
Taxonomic lineageiBacteriaCyanobacteriaSynechococcalesSynechococcaceaeSynechococcus
Proteomesi
  • UP000001688 Componenti: Chromosome

Subcellular locationi

GO - Cellular componenti

Keywords - Cellular componenti

Membrane, Photosystem I, Thylakoid

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi14C → A, D or S: Generates altered FB cluster (in vitro). 2 Publications1
Mutagenesisi21C → D: Unable to bind PSI cores (in vitro). 1 Publication1
Mutagenesisi34C → A or S: No measurable effect. 1 Publication1
Mutagenesisi51C → A, D or S: Generates altered FA cluster (in vitro). 3 Publications1
Mutagenesisi58C → D: Unable to bind PSI cores (in vitro). 1 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Initiator methionineiRemoved1 Publication
ChainiPRO_00000620212 – 81Photosystem I iron-sulfur centerAdd BLAST80

Proteomic databases

PRIDEiP31087

Interactioni

Subunit structurei

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.By similarity

Protein-protein interaction databases

STRINGi32049.SYNPCC7002_A1589

Structurei

Secondary structure

181
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi18 – 20Combined sources3
Beta strandi26 – 30Combined sources5
Beta strandi32 – 34Combined sources3
Beta strandi37 – 41Combined sources5
Beta strandi60 – 63Combined sources4
Turni69 – 71Combined sources3
Beta strandi74 – 79Combined sources6

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1K0TNMR-A2-81[»]
DisProtiDP00935
ProteinModelPortaliP31087
SMRiP31087
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP31087

Family & Domainsi

Domains and Repeats

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Domaini2 – 314Fe-4S ferredoxin-type 1Add BLAST30
Domaini37 – 684Fe-4S ferredoxin-type 2Add BLAST32

Keywords - Domaini

Repeat

Phylogenomic databases

eggNOGiENOG4108Z6M Bacteria
COG1145 LUCA
HOGENOMiHOG000230505
KOiK02691
OMAiAHTVKIY
OrthoDBiPOG091H01RQ

Family and domain databases

HAMAPiMF_01303 PSI_PsaC, 1 hit
InterProiView protein in InterPro
IPR017896 4Fe4S_Fe-S-bd
IPR017900 4Fe4S_Fe_S_CS
IPR017491 PSI_PsaC
PfamiView protein in Pfam
PF12838 Fer4_7, 1 hit
TIGRFAMsiTIGR03048 PS_I_psaC, 1 hit
PROSITEiView protein in PROSITE
PS00198 4FE4S_FER_1, 2 hits
PS51379 4FE4S_FER_2, 2 hits

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

P31087-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MSHSVKIYDT CIGCTQCVRA CPLDVLEMVP WDGCKAGQIA SSPRTEDCVG
60 70 80
CKRCETACPT DFLSIRVYLG AETTRSMGLA Y
Length:81
Mass (Da):8,814
Last modified:January 23, 2007 - v2
Checksum:i57B7D4A3371A4AFB
GO

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
M86238 Genomic DNA Translation: AAA27353.1
CP000951 Genomic DNA Translation: ACA99580.1
RefSeqiWP_012307203.1, NC_010475.1

Genome annotation databases

EnsemblBacteriaiACA99580; ACA99580; SYNPCC7002_A1589
KEGGisyp:SYNPCC7002_A1589

Similar proteinsi

Entry informationi

Entry nameiPSAC_SYNP2
AccessioniPrimary (citable) accession number: P31087
Secondary accession number(s): B1XNQ5
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 1, 1993
Last sequence update: January 23, 2007
Last modified: May 23, 2018
This is version 124 of the entry and version 2 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references

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