ID   KAIB_SYNY3              Reviewed;         105 AA.
AC   P74645;
DT   11-OCT-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1997, sequence version 1.
DT   25-MAY-2022, entry version 129.
DE   RecName: Full=Circadian clock protein KaiB {ECO:0000255|HAMAP-Rule:MF_01835};
GN   Name=kaiB {ECO:0000255|HAMAP-Rule:MF_01835}; OrderedLocusNames=slr0757;
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).
CC   -!- FUNCTION: Component of the KaiABC clock protein complex, which
CC       constitutes the main circadian regulator in cyanobacteria. The KaiABC
CC       complex may act as a promoter-non-specific transcription regulator that
CC       represses transcription, possibly by acting on the state of chromosome
CC       compaction. In the complex, it decreases the phosphorylation status of
CC       KaiC. It has no effect on KaiC by itself, but instead needs the
CC       presence of both KaiA and KaiC, suggesting that it acts by antagonizing
CC       the interaction between KaiA and KaiC. {ECO:0000255|HAMAP-
CC       Rule:MF_01835}.
CC   -!- SUBUNIT: Homodimer. Component of the KaiABC complex, at least composed
CC       of a KaiC homohexamer, a KaiB dimer and two KaiA dimers. The KaiABC
CC       complex also interacts with SasA. {ECO:0000255|HAMAP-Rule:MF_01835}.
CC   -!- INTERACTION:
CC       P74645; P74645: kaiB; NbExp=2; IntAct=EBI-629476, EBI-629476;
CC   -!- SIMILARITY: Belongs to the KaiB family. {ECO:0000255|HAMAP-
CC       Rule:MF_01835}.
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DR   EMBL; BA000022; BAA18761.1; -; Genomic_DNA.
DR   PIR; S76849; S76849.
DR   PDB; 1WWJ; X-ray; 1.90 A; A/B/C/D=1-105.
DR   PDBsum; 1WWJ; -.
DR   AlphaFoldDB; P74645; -.
DR   SMR; P74645; -.
DR   STRING; 1148.1653851; -.
DR   DrugBank; DB03499; D-Malic acid.
DR   DrugBank; DB03366; Imidazole.
DR   DrugBank; DB04455; N,N,N-trimethylglycinium.
DR   PaxDb; P74645; -.
DR   EnsemblBacteria; BAA18761; BAA18761; BAA18761.
DR   KEGG; syn:slr0757; -.
DR   eggNOG; COG4251; Bacteria.
DR   InParanoid; P74645; -.
DR   OMA; NEFKGVY; -.
DR   PhylomeDB; P74645; -.
DR   EvolutionaryTrace; P74645; -.
DR   Proteomes; UP000001425; Chromosome.
DR   GO; GO:0042802; F:identical protein binding; IPI:IntAct.
DR   GO; GO:0007623; P:circadian rhythm; TAS:UniProtKB.
DR   GO; GO:0042326; P:negative regulation of phosphorylation; IEA:InterPro.
DR   CDD; cd02978; KaiB_like; 1.
DR   HAMAP; MF_01835; KaiB; 1.
DR   InterPro; IPR013474; Circ_KaiB.
DR   InterPro; IPR039022; KaiB-like.
DR   InterPro; IPR011649; KaiB_domain.
DR   InterPro; IPR036249; Thioredoxin-like_sf.
DR   PANTHER; PTHR41709; PTHR41709; 1.
DR   Pfam; PF07689; KaiB; 1.
DR   SMART; SM01248; KaiB; 1.
DR   SUPFAM; SSF52833; SSF52833; 1.
DR   TIGRFAMs; TIGR02654; circ_KaiB; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Biological rhythms; Reference proteome.
FT   CHAIN           1..105
FT                   /note="Circadian clock protein KaiB"
FT                   /id="PRO_0000217771"
FT   STRAND          6..16
FT                   /evidence="ECO:0007829|PDB:1WWJ"
FT   HELIX           19..36
FT                   /evidence="ECO:0007829|PDB:1WWJ"
FT   STRAND          39..46
FT                   /evidence="ECO:0007829|PDB:1WWJ"
FT   TURN            47..49
FT                   /evidence="ECO:0007829|PDB:1WWJ"
FT   STRAND          58..60
FT                   /evidence="ECO:0007829|PDB:1WWJ"
FT   HELIX           62..65
FT                   /evidence="ECO:0007829|PDB:1WWJ"
FT   HELIX           66..68
FT                   /evidence="ECO:0007829|PDB:1WWJ"
FT   HELIX           71..82
FT                   /evidence="ECO:0007829|PDB:1WWJ"
FT   STRAND          87..97
FT                   /evidence="ECO:0007829|PDB:1WWJ"
SQ   SEQUENCE   105 AA;  11935 MW;  0A0C8618CF01B23D CRC64;
     MSPFKKTYVL KLYVAGNTPN SVRALKMLKN ILEQEFQGVY ALKVIDVLKN PQLAEEDKIL
     ATPTLAKILP PPVRKIIGDL SDREKVLIGL DLLYDEIRER EAEDQ