ID   PSBU_PHATR              Reviewed;         148 AA.
AC   Q84XB6;
DT   24-JUL-2007, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2003, sequence version 1.
DT   25-MAY-2022, entry version 55.
DE   RecName: Full=Photosystem II 12 kDa extrinsic protein, chloroplastic;
DE   AltName: Full=PS II complex 12 kDa extrinsic protein;
DE   AltName: Full=PSII-U;
DE   Flags: Precursor;
GN   Name=psbU;
OS   Phaeodactylum tricornutum (Diatom).
OC   Eukaryota; Sar; Stramenopiles; Ochrophyta; Bacillariophyta;
OC   Bacillariophyceae; Bacillariophycidae; Naviculales; Phaeodactylaceae;
OC   Phaeodactylum.
OX   NCBI_TaxID=2850;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA / MRNA].
RC   STRAIN=UTEX 646 / Bohlin;
RX   PubMed=15461428; DOI=10.1007/s00239-004-2593-z;
RA   Kilian O., Kroth P.G.;
RT   "Presequence acquisition during secondary endocytobiosis and the possible
RT   role of introns.";
RL   J. Mol. Evol. 58:712-721(2004).
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:0000250}.
CC   -!- SUBUNIT: The oxygen-evolving complex may be composed of PsbO, PsbQ',
CC       PsbV and PsbU. {ECO:0000305}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane
CC       {ECO:0000250}; Peripheral membrane protein {ECO:0000250}; Lumenal side
CC       {ECO:0000250}. Note=Associated with photosystem II at the lumenal side
CC       of the thylakoid membrane. {ECO:0000250}.
CC   -!- PTM: Might be translocated into the thylakoid lumen by the Tat system.
CC       The position of the transit peptide cleavages have not been
CC       experimentally proven.
CC   -!- SIMILARITY: Belongs to the PsbU family. {ECO:0000305}.
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DR   EMBL; AY191865; AAO43195.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q84XB6; -.
DR   SMR; Q84XB6; -.
DR   HOGENOM; CLU_141240_0_0_1; -.
DR   GO; GO:0009535; C:chloroplast thylakoid membrane; IEA:UniProtKB-SubCell.
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:0015979; P:photosynthesis; IEA:UniProtKB-KW.
DR   GO; GO:0042549; P:photosystem II stabilization; IEA:InterPro.
DR   InterPro; IPR010527; PSII_PsbU.
DR   Pfam; PF06514; PsbU; 1.
PE   3: Inferred from homology;
KW   Chloroplast; Electron transport; Membrane; Photosynthesis; Photosystem II;
KW   Plastid; Thylakoid; Transit peptide; Transport.
FT   TRANSIT         1..32
FT                   /note="Chloroplast"
FT                   /evidence="ECO:0000255"
FT   TRANSIT         33..54
FT                   /note="Thylakoid"
FT                   /evidence="ECO:0000255"
FT   CHAIN           55..148
FT                   /note="Photosystem II 12 kDa extrinsic protein,
FT                   chloroplastic"
FT                   /id="PRO_5000089378"
SQ   SEQUENCE   148 AA;  15991 MW;  779C66372618C35A CRC64;
     MKLAVFAVLI STVAAFVAPN GVQRAATTEL NAERREFLSA AAVAAGLAFP LTANAIRDYE
     NVGYLGGSEI VDVNNANVRV YLKMPGLYPT LAGKIASNGP YNAVGDLYNI PGLSGKEKEL
     LKKYESRFTA QKPQADYVID RFNNGLYR