ID   KAIA_NOSS1              Reviewed;         102 AA.
AC   Q8YT42;
DT   11-OCT-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-2002, sequence version 1.
DT   25-MAY-2022, entry version 89.
DE   RecName: Full=Circadian clock protein KaiA;
GN   Name=kaiA; OrderedLocusNames=alr2884;
OS   Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576).
OC   Bacteria; Cyanobacteria; Nostocales; Nostocaceae; Nostoc.
OX   NCBI_TaxID=103690;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=15170179; DOI=10.1038/nsmb781;
RA   Uzumaki T., Fujita M., Nakatsu T., Hayashi F., Shibata H., Itoh N.,
RA   Kato H., Ishiura M.;
RT   "Crystal structure of the C-terminal clock-oscillator domain of the
RT   cyanobacterial KaiA protein.";
RL   Nat. Struct. Mol. Biol. 11:623-631(2004).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=PCC 7120 / SAG 25.82 / UTEX 2576;
RX   PubMed=11759840; DOI=10.1093/dnares/8.5.205;
RA   Kaneko T., Nakamura Y., Wolk C.P., Kuritz T., Sasamoto S., Watanabe A.,
RA   Iriguchi M., Ishikawa A., Kawashima K., Kimura T., Kishida Y., Kohara M.,
RA   Matsumoto M., Matsuno A., Muraki A., Nakazaki N., Shimpo S., Sugimoto M.,
RA   Takazawa M., Yamada M., Yasuda M., Tabata S.;
RT   "Complete genomic sequence of the filamentous nitrogen-fixing
RT   cyanobacterium Anabaena sp. strain PCC 7120.";
RL   DNA Res. 8:205-213(2001).
RN   [3]
RP   X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS), HOMODIMERIZATION, AND MUTAGENESIS OF
RP   ARG-69.
RX   PubMed=15071498; DOI=10.1038/sj.emboj.7600190;
RA   Garces R.G., Wu N., Gillon W., Pai E.F.;
RT   "Anabaena circadian clock proteins KaiA and KaiB reveal a potential common
RT   binding site to their partner KaiC.";
RL   EMBO J. 23:1688-1698(2004).
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-nonspecific transcription regulator that
CC       represses transcription, possibly by acting on the state of chromosome
CC       compaction. In the complex, it enhances the phosphorylation status of
CC       KaiC. In contrast, the presence of KaiB in the complex decreases the
CC       phosphorylation status of KaiC, suggesting that KaiB acts by
CC       antagonizing the interaction between KaiA and KaiC. A KaiA dimer is
CC       sufficient to enhance KaiC hexamer phosphorylation (By similarity).
CC       {ECO:0000250}.
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 (By similarity). {ECO:0000250}.
CC   -!- DOMAIN: The KaiA domain mediates the interaction with KaiC, the
CC       homodimerization, and is responsible for the clock oscillation
CC       function. {ECO:0000250}.
CC   -!- MISCELLANEOUS: Lacks an N-terminus part downstream the KaiA domain,
CC       which may be involved in transducing input signals to the KaiABC
CC       complex.
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DR   EMBL; AB071284; BAB85867.1; -; Genomic_DNA.
DR   EMBL; BA000019; BAB74583.1; -; Genomic_DNA.
DR   PIR; AE2166; AE2166.
DR   RefSeq; WP_010997035.1; NZ_RSCN01000003.1.
DR   PDB; 1R5Q; X-ray; 2.00 A; A=1-102.
DR   PDBsum; 1R5Q; -.
DR   AlphaFoldDB; Q8YT42; -.
DR   SMR; Q8YT42; -.
DR   STRING; 103690.17131978; -.
DR   EnsemblBacteria; BAB74583; BAB74583; BAB74583.
DR   KEGG; ana:alr2884; -.
DR   eggNOG; ENOG502Z8HQ; Bacteria.
DR   OMA; LCEAYRG; -.
DR   OrthoDB; 1644154at2; -.
DR   EvolutionaryTrace; Q8YT42; -.
DR   Proteomes; UP000002483; Chromosome.
DR   GO; GO:0007623; P:circadian rhythm; IEA:InterPro.
DR   GO; GO:0006468; P:protein phosphorylation; IEA:InterPro.
DR   Gene3D; 1.10.1240.30; -; 1.
DR   InterPro; IPR011648; Circadian_clock_KaiA.
DR   InterPro; IPR020856; Circadian_clock_protein_KaiA_C.
DR   InterPro; IPR017944; KaiA/RbsU_helical_domain_sf.
DR   Pfam; PF07688; KaiA; 1.
DR   SMART; SM01247; KaiA; 1.
DR   SUPFAM; SSF101215; SSF101215; 1.
DR   PROSITE; PS51431; KAIA_C; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Biological rhythms; Reference proteome.
FT   CHAIN           1..102
FT                   /note="Circadian clock protein KaiA"
FT                   /id="PRO_0000217868"
FT   DOMAIN          1..102
FT                   /note="KaiA C-terminal"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00761"
FT   MUTAGEN         69
FT                   /note="R->A: Abolishes the interaction with KaiC."
FT                   /evidence="ECO:0000269|PubMed:15071498"
FT   HELIX           8..24
FT                   /evidence="ECO:0007829|PDB:1R5Q"
FT   HELIX           33..45
FT                   /evidence="ECO:0007829|PDB:1R5Q"
FT   HELIX           50..67
FT                   /evidence="ECO:0007829|PDB:1R5Q"
FT   HELIX           79..81
FT                   /evidence="ECO:0007829|PDB:1R5Q"
FT   HELIX           82..100
FT                   /evidence="ECO:0007829|PDB:1R5Q"
SQ   SEQUENCE   102 AA;  11965 MW;  552AA7370BA9D74C CRC64;
     MTQEVDQQIL LQQLKSDYRQ ILLSYFTTDK ALKEKIDKFI NAVFCANIPV PEIIEIHMEL
     IDEFSKQLRL EGRGDETLMD YRLTLIDILA HLCEAYRGAI FK