ID   KAIC_RIPO1              Reviewed;         521 AA.
AC   Q8VL13; B7K6A2;
DT   11-OCT-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-2002, sequence version 1.
DT   03-AUG-2022, entry version 106.
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};
GN   OrderedLocusNames=PCC8801_4231;
OS   Rippkaea orientalis (strain PCC 8801) (Cyanothece sp. (strain PCC 8801)).
OC   Bacteria; Cyanobacteria; Oscillatoriophycideae; Chroococcales;
OC   Aphanothecaceae; Rippkaea; Rippkaea orientalis.
OX   NCBI_TaxID=41431;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RA   Lin R.-F., Huang T.-C., Chen L.-R.;
RT   "Hypothetical kaiB and kaiC genes in Synechococcus RF-1.";
RL   Submitted (OCT-2001) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=PCC 8801;
RX   PubMed=21972240; DOI=10.1128/mbio.00214-11;
RA   Bandyopadhyay A., Elvitigala T., Welsh E., Stockel J., Liberton M., Min H.,
RA   Sherman L.A., Pakrasi H.B.;
RT   "Novel metabolic attributes of the genus Cyanothece, comprising a group of
RT   unicellular nitrogen-fixing Cyanobacteria.";
RL   MBio 2:E214-E214(2011).
CC   -!- FUNCTION: Core component of the KaiABC clock protein complex, which
CC       constitutes the main circadian regulator in cyanobacteria. Binds to
CC       DNA. The KaiABC 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   -!- ACTIVITY REGULATION: The interaction with KaiA enhances its
CC       phosphorylation status, while the interaction with KaiB decreases it. A
CC       KaiA dimer is sufficient to enhance KaiC phosphorylation.
CC       {ECO:0000255|HAMAP-Rule:MF_01836}.
CC   -!- SUBUNIT: Homohexamer; hexamerization is dependent on ATP-binding. Core
CC       component of the KaiABC complex, at least composed of a KaiC
CC       homohexamer, a KaiB dimer and two KaiA dimers. Interacts directly with
CC       SasA. {ECO:0000255|HAMAP-Rule:MF_01836}.
CC   -!- DOMAIN: The KaiC domains mediate the interaction with KaiA.
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; AF442204; AAL34546.1; -; Genomic_DNA.
DR   EMBL; CP001287; ACK68155.1; -; Genomic_DNA.
DR   RefSeq; WP_015785209.1; NC_011726.1.
DR   AlphaFoldDB; Q8VL13; -.
DR   SMR; Q8VL13; -.
DR   STRING; 41431.PCC8801_4231; -.
DR   EnsemblBacteria; ACK68155; ACK68155; PCC8801_4231.
DR   KEGG; cyp:PCC8801_4231; -.
DR   eggNOG; COG0467; Bacteria.
DR   HOGENOM; CLU_023669_4_1_3; -.
DR   OMA; MGSHSIT; -.
DR   OrthoDB; 271085at2; -.
DR   Proteomes; UP000008204; 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; Reference proteome;
KW   Repeat; Repressor; Serine/threonine-protein kinase; Transcription;
KW   Transcription regulation; Transferase.
FT   CHAIN           1..521
FT                   /note="Circadian clock protein kinase KaiC"
FT                   /id="PRO_0000217783"
FT   DOMAIN          20..261
FT                   /note="KaiC 1"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   DOMAIN          262..494
FT                   /note="KaiC 2"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         47..54
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         289..296
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         296
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         319
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         320
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   BINDING         379
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
FT   MOD_RES         433
FT                   /note="Phosphothreonine; by autocatalysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01836"
SQ   SEQUENCE   521 AA;  58303 MW;  946397BF2270C55C CRC64;
     MNEPISNSSK KTENTTQGVR KIRTMIEGFD EITHGGLPIG RTTLVSGTSG TGKTLLAVQF
     LYHGIKYFDY PGLFVTFEES PTDIIQNAYS FGWDLQEIVD EGKLFILDAS PDPDGQEVVG
     SFDLSALIER IQYAINKYKA QLVSIDSVTA VFQQYDAASV VRREIFRLVA RLKLLGVTSI
     MTTERIEEYG PIARYGVEEF VSDNVVVLRN VLEGERRRRT AEILKLRGTT HMKGEYPFTI
     TNDGINIFPL GAMRLTQRSS NARISSGVKT LDEMCGGGFF KDSIILATGA TGTGKTLLVS
     KFLEEGCRQG ERAILFAYEE SRAQLSRNAF SWGIDFEEME RKGLLKLLCS YPESAGLEDH
     LQIIKSEISE FKPSRIAIDS LSALARGVTN NAFRQFVIGV TGYAKQEEIT GFFTNTTDQF
     MGAHSITESH ISTITDTIIM LQYVEIRGEM SRAINVFKMR GSWHDKGIRE YSINESGPTI
     QDSFRNYERI ISGSPTRITV DEKNELSRIV RGVKDKTLDE E