ID   PSBI_PROM1              Reviewed;          42 AA.
AC   A2C085;
DT   21-AUG-2007, integrated into UniProtKB/Swiss-Prot.
DT   20-FEB-2007, sequence version 1.
DT   25-MAY-2022, entry version 72.
DE   RecName: Full=Photosystem II reaction center protein I {ECO:0000255|HAMAP-Rule:MF_01316};
DE            Short=PSII-I {ECO:0000255|HAMAP-Rule:MF_01316};
DE   AltName: Full=PSII 4.4 kDa protein {ECO:0000255|HAMAP-Rule:MF_01316};
GN   Name=psbI {ECO:0000255|HAMAP-Rule:MF_01316}; OrderedLocusNames=NATL1_03311;
OS   Prochlorococcus marinus (strain NATL1A).
OC   Bacteria; Cyanobacteria; Synechococcales; Prochlorococcaceae;
OC   Prochlorococcus.
OX   NCBI_TaxID=167555;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=NATL1A;
RX   PubMed=18159947; DOI=10.1371/journal.pgen.0030231;
RA   Kettler G.C., Martiny A.C., Huang K., Zucker J., Coleman M.L., Rodrigue S.,
RA   Chen F., Lapidus A., Ferriera S., Johnson J., Steglich C., Church G.M.,
RA   Richardson P., Chisholm S.W.;
RT   "Patterns and implications of gene gain and loss in the evolution of
RT   Prochlorococcus.";
RL   PLoS Genet. 3:2515-2528(2007).
CC   -!- FUNCTION: One of the components of the core complex of photosystem II
CC       (PSII), required for its stability and/or assembly. PSII is a light-
CC       driven water:plastoquinone oxidoreductase that uses light energy to
CC       abstract electrons from H(2)O, generating O(2) and a proton gradient
CC       subsequently used for ATP formation. It consists of a core antenna
CC       complex that captures photons, and an electron transfer chain that
CC       converts photonic excitation into a charge separation.
CC       {ECO:0000255|HAMAP-Rule:MF_01316}.
CC   -!- SUBUNIT: Cyanobacterial PSII is composed of 1 copy each of membrane
CC       proteins PsbA, PsbB, PsbC, PsbD, PsbE, PsbF, PsbH, PsbI, PsbJ, PsbK,
CC       PsbL, PsbM, PsbT, PsbX, PsbY, PsbZ, Ycf12, at least 3 peripheral
CC       proteins PsbO, PsbU, PsbV and a large number of cofactors. It forms
CC       dimeric complexes. {ECO:0000255|HAMAP-Rule:MF_01316}.
CC   -!- SUBCELLULAR LOCATION: Cellular thylakoid membrane {ECO:0000255|HAMAP-
CC       Rule:MF_01316}; Single-pass membrane protein {ECO:0000255|HAMAP-
CC       Rule:MF_01316}.
CC   -!- SIMILARITY: Belongs to the PsbI family. {ECO:0000255|HAMAP-
CC       Rule:MF_01316}.
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DR   EMBL; CP000553; ABM74895.1; -; Genomic_DNA.
DR   RefSeq; WP_011294252.1; NC_008819.1.
DR   AlphaFoldDB; A2C085; -.
DR   SMR; A2C085; -.
DR   STRING; 167555.NATL1_03311; -.
DR   EnsemblBacteria; ABM74895; ABM74895; NATL1_03311.
DR   KEGG; pme:NATL1_03311; -.
DR   HOGENOM; CLU_212150_0_0_3; -.
DR   Proteomes; UP000002592; Chromosome.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0009539; C:photosystem II reaction center; IEA:InterPro.
DR   GO; GO:0031676; C:plasma membrane-derived thylakoid membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0015979; P:photosynthesis; IEA:UniProtKB-UniRule.
DR   HAMAP; MF_01316; PSII_PsbI; 1.
DR   InterPro; IPR003686; PSII_PsbI.
DR   InterPro; IPR037271; PSII_PsbI_sf.
DR   Pfam; PF02532; PsbI; 1.
DR   SUPFAM; SSF161041; SSF161041; 1.
PE   3: Inferred from homology;
KW   Membrane; Photosynthesis; Photosystem II; Reaction center; Thylakoid;
KW   Transmembrane; Transmembrane helix.
FT   CHAIN           1..42
FT                   /note="Photosystem II reaction center protein I"
FT                   /id="PRO_0000298300"
FT   TRANSMEM        6..26
FT                   /note="Helical"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01316"
SQ   SEQUENCE   42 AA;  4782 MW;  0117BD2AF19BE3F0 CRC64;
     MLALKISVYT VVFFFVGIFL FGFLASDPTR TPNRKDLESP QD