ID   KAIC_PROMP              Reviewed;         509 AA.
AC   Q7V0C4;
DT   11-OCT-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2003, sequence version 1.
DT   03-AUG-2022, entry version 113.
DE   RecName: Full=Circadian clock protein kinase KaiC {ECO:0000255|HAMAP-Rule:MF_01836};
DE            EC=2.7.11.1 {ECO:0000255|HAMAP-Rule:MF_01836};
GN   Name=kaiC {ECO:0000255|HAMAP-Rule:MF_01836}; OrderedLocusNames=PMM1342;
OS   Prochlorococcus marinus subsp. pastoris (strain CCMP1986 / NIES-2087 /
OS   MED4).
OC   Bacteria; Cyanobacteria; Synechococcales; Prochlorococcaceae;
OC   Prochlorococcus.
OX   NCBI_TaxID=59919;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=CCMP1986 / NIES-2087 / MED4;
RX   PubMed=12917642; DOI=10.1038/nature01947;
RA   Rocap G., Larimer F.W., Lamerdin J.E., Malfatti S., Chain P., Ahlgren N.A.,
RA   Arellano A., Coleman M., Hauser L., Hess W.R., Johnson Z.I., Land M.L.,
RA   Lindell D., Post A.F., Regala W., Shah M., Shaw S.L., Steglich C.,
RA   Sullivan M.B., Ting C.S., Tolonen A., Webb E.A., Zinser E.R.,
RA   Chisholm S.W.;
RT   "Genome divergence in two Prochlorococcus ecotypes reflects oceanic niche
RT   differentiation.";
RL   Nature 424:1042-1047(2003).
CC   -!- FUNCTION: Core component of the KaiBC clock protein complex, which
CC       constitutes the main circadian regulator in cyanobacteria. Binds to
CC       DNA. The KaiBC complex may act as a promoter-nonspecific transcription
CC       regulator that represses transcription, possibly by acting on the state
CC       of chromosome compaction. {ECO:0000255|HAMAP-Rule:MF_01836}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-
CC         [protein]; Xref=Rhea:RHEA:17989, Rhea:RHEA-COMP:9863, Rhea:RHEA-
CC         COMP:11604, ChEBI:CHEBI:15378, ChEBI:CHEBI:29999, ChEBI:CHEBI:30616,
CC         ChEBI:CHEBI:83421, ChEBI:CHEBI:456216; EC=2.7.11.1;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_01836};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-
CC         threonyl-[protein]; Xref=Rhea:RHEA:46608, Rhea:RHEA-COMP:11060,
CC         Rhea:RHEA-COMP:11605, ChEBI:CHEBI:15378, ChEBI:CHEBI:30013,
CC         ChEBI:CHEBI:30616, ChEBI:CHEBI:61977, ChEBI:CHEBI:456216;
CC         EC=2.7.11.1; Evidence={ECO:0000255|HAMAP-Rule:MF_01836};
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_01836};
CC   -!- SUBUNIT: Homohexamer; hexamerization is dependent on ATP-binding.
CC       Component of the KaiBC complex with KaiB. Interacts directly with SasA.
CC       {ECO:0000255|HAMAP-Rule:MF_01836}.
CC   -!- PTM: Phosphorylated on serine/threonine residues by autocatalysis. Both
CC       phosphorylated and unphosphorylated forms exist. Can probably
CC       autophosphorylate and autodephosphorylate. Phosphorylated form
CC       correlates with clock speed. {ECO:0000255|HAMAP-Rule:MF_01836}.
CC   -!- SIMILARITY: Belongs to the KaiC family. {ECO:0000255|HAMAP-
CC       Rule:MF_01836}.
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DR   EMBL; BX548174; CAE19801.1; -; Genomic_DNA.
DR   RefSeq; WP_011132976.1; NC_005072.1.
DR   AlphaFoldDB; Q7V0C4; -.
DR   SMR; Q7V0C4; -.
DR   STRING; 59919.PMM1342; -.
DR   EnsemblBacteria; CAE19801; CAE19801; PMM1342.
DR   KEGG; pmm:PMM1342; -.
DR   eggNOG; COG0467; Bacteria.
DR   HOGENOM; CLU_023669_4_1_3; -.
DR   OMA; MGSHSIT; -.
DR   OrthoDB; 271085at2; -.
DR   Proteomes; UP000001026; Chromosome.
DR   GO; GO:0005524; F:ATP binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0000287; F:magnesium ion binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0106310; F:protein serine kinase activity; IEA:RHEA.
DR   GO; GO:0004674; F:protein serine/threonine kinase activity; IEA:UniProtKB-KW.
DR   GO; GO:0004712; F:protein serine/threonine/tyrosine kinase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0007623; P:circadian rhythm; IEA:UniProtKB-UniRule.
DR   GO; GO:0016310; P:phosphorylation; IEA:UniProtKB-KW.
DR   GO; GO:0042752; P:regulation of circadian rhythm; IEA:InterPro.
DR   GO; GO:0006355; P:regulation of transcription, DNA-templated; IEA:InterPro.
DR   Gene3D; 3.40.50.300; -; 2.
DR   HAMAP; MF_01836; KaiC; 1.
DR   InterPro; IPR013503; Circadian_KaiC_bact.
DR   InterPro; IPR030665; KaiC.
DR   InterPro; IPR014774; KaiC-like_dom.
DR   InterPro; IPR010624; KaiC_dom.
DR   InterPro; IPR027417; P-loop_NTPase.
DR   Pfam; PF06745; ATPase; 2.
DR   PIRSF; PIRSF039117; KaiC; 1.
DR   SUPFAM; SSF52540; SSF52540; 2.
DR   TIGRFAMs; TIGR02655; circ_KaiC; 1.
DR   PROSITE; PS51146; KAIC; 2.
PE   3: Inferred from homology;
KW   ATP-binding; Biological rhythms; DNA-binding; Kinase; Magnesium;
KW   Metal-binding; Nucleotide-binding; Phosphoprotein; Repeat; Repressor;
KW   Serine/threonine-protein kinase; Transcription; Transcription regulation;
KW   Transferase.
FT   CHAIN           1..509
FT                   /note="Circadian clock protein kinase KaiC"
FT                   /id="PRO_0000217778"
FT   DOMAIN          15..256
FT                   /note="KaiC 1"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   DOMAIN          257..489
FT                   /note="KaiC 2"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         42..49
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         284..291
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         291
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         314
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         315
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         374
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   MOD_RES         428
FT                   /note="Phosphothreonine; by autocatalysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
SQ   SEQUENCE   509 AA;  56950 MW;  0811D71145BA173C CRC64;
     MKDKKISKSI KMQVQKIPTG IEGFDDVCRG GLPAARSTLV SGTSGTGKTV FSLQYLHHGI
     CNFDEPGIFI TFEESPLDII RNAASFGWDL QKLIDQNKLF ILDASPDPDG QDVAGNFDLS
     GLIERISYAI RKYKAKRVAI DSITAVFQQY DAIYVVRREI FRLIARLKEI GVTTVMTTER
     VDDYGPIARY GVEEFVSDNV VLLRNVLEAE KRRRTLEVLK LRGTVHMKGE FPFTMGDDGI
     IVFALGAMRL TQRSSNIRIS SGVKDLDEMC GGGYFQDSII LATGATGTGK TMLVSKFIED
     AYNNKERAIL FAYEESRAQL NRNATSWGID FEKMENEGLL KIICAYPEST GLEDHLQIIK
     SQINEFKPKR LAIDSLSALA RGVSLNAFRQ FVIGVTGYSK QEEIAGFFTN TAEEFMGSHS
     ITDSHISTIT DTILLLQYVE IKGEMARAIN VFKMRGSWHD KRIREYIITG QGPEIKDSFS
     NFEQIFSGAP HRVISDQSIP NVFKGIEKN