ID   PSBU_CROS5              Reviewed;         122 AA.
AC   O50291; B1WT51;
DT   01-NOV-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-1998, sequence version 1.
DT   25-MAY-2022, entry version 100.
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=cce_2625;
OS   Crocosphaera subtropica (strain ATCC 51142 / BH68) (Cyanothece sp. (strain
OS   ATCC 51142)).
OC   Bacteria; Cyanobacteria; Oscillatoriophycideae; Chroococcales;
OC   Aphanothecaceae; Crocosphaera; Crocosphaera subtropica.
OX   NCBI_TaxID=43989;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=BH68K;
RA   Meunier P.C., Tang H.-Y., Sherman L.A.;
RT   "Cloning and sequencing of the psbU gene from the cyanobacterium Cyanothece
RT   sp. ATCC 51142.";
RL   (er) Plant Gene Register PGR98-036(1998).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 51142 / BH68;
RX   PubMed=18812508; DOI=10.1073/pnas.0805418105;
RA   Welsh E.A., Liberton M., Stoeckel J., Loh T., Elvitigala T., Wang C.,
RA   Wollam A., Fulton R.S., Clifton S.W., Jacobs J.M., Aurora R., Ghosh B.K.,
RA   Sherman L.A., Smith R.D., Wilson R.K., Pakrasi H.B.;
RT   "The genome of Cyanothece 51142, a unicellular diazotrophic cyanobacterium
RT   important in the marine nitrogen cycle.";
RL   Proc. Natl. Acad. Sci. U.S.A. 105:15094-15099(2008).
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=ACB51973.1; Type=Erroneous initiation; Evidence={ECO:0000305};
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DR   EMBL; AF036250; AAD10131.1; -; Genomic_DNA.
DR   EMBL; CP000806; ACB51973.1; ALT_INIT; Genomic_DNA.
DR   RefSeq; WP_009544685.1; NC_010546.1.
DR   AlphaFoldDB; O50291; -.
DR   SMR; O50291; -.
DR   STRING; 43989.cce_2625; -.
DR   PRIDE; O50291; -.
DR   EnsemblBacteria; ACB51973; ACB51973; cce_2625.
DR   KEGG; cyt:cce_2625; -.
DR   eggNOG; COG1555; Bacteria.
DR   HOGENOM; CLU_141240_1_0_3; -.
DR   OMA; LLGCWGW; -.
DR   OrthoDB; 1626529at2; -.
DR   Proteomes; UP000001203; Chromosome circular.
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..26
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00589"
FT   CHAIN           27..122
FT                   /note="Photosystem II 12 kDa extrinsic protein"
FT                   /id="PRO_0000029598"
SQ   SEQUENCE   122 AA;  13573 MW;  B583FF978E24D0BE CRC64;
     MKTIVRLFAI LMVLISSVGF VGSAVAAELN PVDAKLTTEY GQKIDLNNED VRGFRQLRGF
     YPNLAAKIIK YSPYDSVEEV LDIPGLSERQ RQRLEANLDK FVVTPPSSEL NEGGDRINPG
     LY