ID   PSBU_NOSS1              Reviewed;         142 AA.
AC   Q8YXJ7;
DT   01-NOV-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-2002, sequence version 2.
DT   25-MAY-2022, entry version 95.
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}; OrderedLocusNames=alr1216;
OS   Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576).
OC   Bacteria; Cyanobacteria; Nostocales; Nostocaceae; Nostoc.
OX   NCBI_TaxID=103690;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=PCC 7120 / SAG 25.82 / UTEX 2576;
RX   PubMed=11759840; DOI=10.1093/dnares/8.5.205;
RA   Kaneko T., Nakamura Y., Wolk C.P., Kuritz T., Sasamoto S., Watanabe A.,
RA   Iriguchi M., Ishikawa A., Kawashima K., Kimura T., Kishida Y., Kohara M.,
RA   Matsumoto M., Matsuno A., Muraki A., Nakazaki N., Shimpo S., Sugimoto M.,
RA   Takazawa M., Yamada M., Yasuda M., Tabata S.;
RT   "Complete genomic sequence of the filamentous nitrogen-fixing
RT   cyanobacterium Anabaena sp. strain PCC 7120.";
RL   DNA Res. 8:205-213(2001).
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}.
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}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=BAB73173.1; Type=Erroneous initiation; Evidence={ECO:0000305};
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DR   EMBL; BA000019; BAB73173.1; ALT_INIT; Genomic_DNA.
DR   PIR; AE1958; AE1958.
DR   RefSeq; WP_044522799.1; NZ_RSCN01000021.1.
DR   AlphaFoldDB; Q8YXJ7; -.
DR   SMR; Q8YXJ7; -.
DR   STRING; 103690.17130563; -.
DR   EnsemblBacteria; BAB73173; BAB73173; BAB73173.
DR   KEGG; ana:alr1216; -.
DR   eggNOG; COG1555; Bacteria.
DR   OMA; LLGCWGW; -.
DR   OrthoDB; 1626529at2; -.
DR   Proteomes; UP000002483; 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   3: Inferred from homology;
KW   Electron transport; Membrane; Photosynthesis; Photosystem II;
KW   Reference proteome; Signal; Thylakoid; Transport.
FT   SIGNAL          1..29
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00589"
FT   CHAIN           30..142
FT                   /note="Photosystem II 12 kDa extrinsic protein"
FT                   /id="PRO_0000029597"
SQ   SEQUENCE   142 AA;  15845 MW;  A8E803E50F091E8B CRC64;
     MKGLVRLLTV FSLLLGCWGW LGTTQIAQAG SLQSFLVPQI PVLAIERQNR ADAKLATEFG
     EKIDLNNTNV RAFQQYPGLY PTLAKKIIQN APYGKVEDVL NLPGLSDGQK QLLQSNFDKF
     TVTELEPAFN EGDDRFNNGI YR