ID   PSBU_SYNP2              Reviewed;         138 AA.
AC   P74765; B1XNF4;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1997, sequence version 1.
DT   25-MAY-2022, entry version 118.
DE   RecName: Full=Photosystem II 12 kDa extrinsic protein {ECO:0000255|HAMAP-Rule:MF_00589};
DE   AltName: Full=PS II complex 12 kDa extrinsic protein {ECO:0000255|HAMAP-Rule:MF_00589};
DE   AltName: Full=PSII-U {ECO:0000255|HAMAP-Rule:MF_00589};
DE   Flags: Precursor;
GN   Name=psbU {ECO:0000255|HAMAP-Rule:MF_00589};
GN   OrderedLocusNames=SYNPCC7002_A0322;
OS   Synechococcus sp. (strain ATCC 27264 / PCC 7002 / PR-6) (Agmenellum
OS   quadruplicatum).
OC   Bacteria; Cyanobacteria; Synechococcales; Synechococcaceae; Synechococcus;
OC   unclassified Synechococcus.
OX   NCBI_TaxID=32049;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], AND PROTEIN SEQUENCE OF 43-101.
RX   PubMed=9414557; DOI=10.1104/pp.115.4.1473;
RA   Nishiyama Y., Los D.A., Hayashi H., Murata N.;
RT   "Thermal protection of the oxygen-evolving machinery by PsbU, an extrinsic
RT   protein of photosystem II, in Synechococcus species PCC 7002.";
RL   Plant Physiol. 115:1473-1480(1997).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 27264 / PCC 7002 / PR-6;
RA   Li T., Zhao J., Zhao C., Liu Z., Zhao F., Marquardt J., Nomura C.T.,
RA   Persson S., Detter J.C., Richardson P.M., Lanz C., Schuster S.C., Wang J.,
RA   Li S., Huang X., Cai T., Yu Z., Luo J., Zhao J., Bryant D.A.;
RT   "Complete sequence of Synechococcus sp. PCC 7002.";
RL   Submitted (FEB-2008) to the EMBL/GenBank/DDBJ databases.
RN   [3]
RP   FUNCTION.
RX   PubMed=10318707; DOI=10.1104/pp.120.1.301;
RA   Nishiyama Y., Los D.A., Murata N.;
RT   "PsbU, a protein associated with photosystem II, is required for the
RT   acquisition of cellular thermotolerance in Synechococcus species PCC
RT   7002.";
RL   Plant Physiol. 120:301-308(1999).
CC   -!- FUNCTION: Stabilizes the structure of photosystem II oxygen-evolving
CC       complex (OEC), the ion environment of oxygen evolution and protects the
CC       OEC against heat-induced inactivation. {ECO:0000255|HAMAP-
CC       Rule:MF_00589, ECO:0000269|PubMed:10318707}.
CC   -!- SUBUNIT: With PsbO,P,Q and V forms the oxygen-evolving complex of
CC       photosystem II. {ECO:0000255|HAMAP-Rule:MF_00589}.
CC   -!- SUBCELLULAR LOCATION: Cellular thylakoid membrane {ECO:0000255|HAMAP-
CC       Rule:MF_00589}; Peripheral membrane protein {ECO:0000255|HAMAP-
CC       Rule:MF_00589}; Lumenal side {ECO:0000255|HAMAP-Rule:MF_00589}.
CC       Note=Associated with photosystem II at the lumenal side of the
CC       thylakoid membrane. {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the PsbU family. {ECO:0000255|HAMAP-
CC       Rule:MF_00589}.
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DR   EMBL; X93509; CAA63766.1; -; Genomic_DNA.
DR   EMBL; CP000951; ACA98332.1; -; Genomic_DNA.
DR   RefSeq; WP_012305956.1; NC_010475.1.
DR   AlphaFoldDB; P74765; -.
DR   SMR; P74765; -.
DR   STRING; 32049.SYNPCC7002_A0322; -.
DR   EnsemblBacteria; ACA98332; ACA98332; SYNPCC7002_A0322.
DR   KEGG; syp:SYNPCC7002_A0322; -.
DR   eggNOG; COG1555; Bacteria.
DR   HOGENOM; CLU_141240_1_0_3; -.
DR   Proteomes; UP000001688; Chromosome.
DR   GO; GO:0019898; C:extrinsic component of membrane; IEA:InterPro.
DR   GO; GO:0009654; C:photosystem II oxygen evolving complex; 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   GO; GO:0042549; P:photosystem II stabilization; IEA:InterPro.
DR   HAMAP; MF_00589; PSII_PsbU; 1.
DR   InterPro; IPR010527; PSII_PsbU.
DR   Pfam; PF06514; PsbU; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Electron transport; Membrane; Photosynthesis;
KW   Photosystem II; Reference proteome; Signal; Thylakoid; Transport.
FT   SIGNAL          1..28
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00589"
FT   PROPEP          29..42
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000029603"
FT   CHAIN           43..138
FT                   /note="Photosystem II 12 kDa extrinsic protein"
FT                   /id="PRO_0000029604"
SQ   SEQUENCE   138 AA;  15342 MW;  1402C70483FDBE71 CRC64;
     MSRVVSALMG LVLMFGCAFF SVQPQAQALD LSNGFVSAAV LGERVNPADK VLESEYGKKI
     DLNNASVRLF RELRGFYPTL AKRIIENAPY DSVEDVLNIP DLSEKQLARL EENLERFTVT
     PPADVFIDGD QRLNTGDY