ID   PSBX_SYNY3              Reviewed;          39 AA.
AC   P72575;
DT   22-JUL-2008, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1997, sequence version 1.
DT   03-AUG-2022, entry version 110.
DE   RecName: Full=Photosystem II reaction center X protein;
GN   Name=psbX; OrderedLocusNames=sml0002;
OS   Synechocystis sp. (strain PCC 6803 / Kazusa).
OC   Bacteria; Cyanobacteria; Synechococcales; Merismopediaceae; Synechocystis;
OC   unclassified Synechocystis.
OX   NCBI_TaxID=1111708;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=PCC 6803 / Kazusa;
RX   PubMed=8905231; DOI=10.1093/dnares/3.3.109;
RA   Kaneko T., Sato S., Kotani H., Tanaka A., Asamizu E., Nakamura Y.,
RA   Miyajima N., Hirosawa M., Sugiura M., Sasamoto S., Kimura T., Hosouchi T.,
RA   Matsuno A., Muraki A., Nakazaki N., Naruo K., Okumura S., Shimpo S.,
RA   Takeuchi C., Wada T., Watanabe A., Yamada M., Yasuda M., Tabata S.;
RT   "Sequence analysis of the genome of the unicellular cyanobacterium
RT   Synechocystis sp. strain PCC6803. II. Sequence determination of the entire
RT   genome and assignment of potential protein-coding regions.";
RL   DNA Res. 3:109-136(1996).
RN   [2]
RP   PROTEIN SEQUENCE OF 1-9, SUBUNIT, AND SUBCELLULAR LOCATION.
RC   STRAIN=PCC 6803 / Kazusa;
RX   PubMed=12069591; DOI=10.1021/bi026012+;
RA   Kashino Y., Lauber W.M., Carroll J.A., Wang Q., Whitmarsh J., Satoh K.,
RA   Pakrasi H.B.;
RT   "Proteomic analysis of a highly active photosystem II preparation from the
RT   cyanobacterium Synechocystis sp. PCC 6803 reveals the presence of novel
RT   polypeptides.";
RL   Biochemistry 41:8004-8012(2002).
RN   [3]
RP   DISRUPTION PHENOTYPE, INDUCTION, AND FUNCTION.
RX   PubMed=11202442; DOI=10.1023/a:1026764728846;
RA   Funk C.;
RT   "Functional analysis of the PsbX protein by deletion of the corresponding
RT   gene in Synechocystis sp. PCC 6803.";
RL   Plant Mol. Biol. 44:815-827(2000).
CC   -!- FUNCTION: Involved in the binding and/or turnover of quinones at the
CC       Q(B) site of Photosystem II. {ECO:0000250,
CC       ECO:0000269|PubMed:11202442}.
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:0000269|PubMed:12069591}.
CC   -!- SUBCELLULAR LOCATION: Cellular thylakoid membrane {ECO:0000250,
CC       ECO:0000269|PubMed:12069591}; Single-pass membrane protein
CC       {ECO:0000250}.
CC   -!- INDUCTION: By high-light stress. {ECO:0000269|PubMed:11202442}.
CC   -!- DISRUPTION PHENOTYPE: Cells have about 30% less PSII and a minor
CC       uncoupling of the antenna. {ECO:0000269|PubMed:11202442}.
CC   -!- SIMILARITY: Belongs to the PsbX family. Type 1 subfamily.
CC       {ECO:0000305}.
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DR   EMBL; BA000022; BAA10311.1; -; Genomic_DNA.
DR   PIR; S74393; S74393.
DR   PDB; 6WJ6; EM; 2.58 A; X=1-39.
DR   PDB; 7N8O; EM; 1.93 A; X/x=1-39.
DR   PDB; 7RCV; EM; 2.01 A; X/x=1-39.
DR   PDBsum; 6WJ6; -.
DR   PDBsum; 7N8O; -.
DR   PDBsum; 7RCV; -.
DR   AlphaFoldDB; P72575; -.
DR   SMR; P72575; -.
DR   IntAct; P72575; 1.
DR   STRING; 1148.1673306; -.
DR   PaxDb; P72575; -.
DR   EnsemblBacteria; BAA10311; BAA10311; BAA10311.
DR   KEGG; syn:sml0002; -.
DR   eggNOG; ENOG5033AJK; Bacteria.
DR   InParanoid; P72575; -.
DR   BioCyc; MetaCyc:PSBX-MON; -.
DR   Proteomes; UP000001425; Chromosome.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0031676; C:plasma membrane-derived thylakoid membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0030096; C:plasma membrane-derived thylakoid photosystem II; IDA:UniProtKB.
DR   GO; GO:0015979; P:photosynthesis; IEA:UniProtKB-UniRule.
DR   HAMAP; MF_01386; PSII_PsbX_1; 1.
DR   InterPro; IPR009518; PSII_PsbX.
DR   InterPro; IPR023431; PSII_PsbX_type_1_subfam.
DR   Pfam; PF06596; PsbX; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Direct protein sequencing; Membrane; Photosynthesis;
KW   Photosystem II; Reference proteome; Thylakoid; Transmembrane;
KW   Transmembrane helix.
FT   CHAIN           1..39
FT                   /note="Photosystem II reaction center X protein"
FT                   /id="PRO_0000345385"
FT   TRANSMEM        10..30
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   HELIX           3..18
FT                   /evidence="ECO:0007829|PDB:7N8O"
FT   HELIX           20..33
FT                   /evidence="ECO:0007829|PDB:7N8O"
SQ   SEQUENCE   39 AA;  4186 MW;  E4F522F0281AC33D CRC64;
     MTPSLANFLW SLVLGAAIVL IPATVGLIFI SQKDKITRS