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Annotation rule MF_01836
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General rule information [?]

Accession MF_01836
Dates 13-SEP-2004 (Created)
19-NOV-2019 (Last updated, Version 23)
Name KaiC
Scope
Bacteria; Cyanobacteria
Templates Q79PF4 (KAIC_SYNE7); Q79V60 (KAIC_THEEB): [Recover all]
Triggered by

Propagated annotation [?]


Identifier, protein and gene names [?]

Identifier
KAIC
Protein name
RecName: Full=Circadian clock protein kinase KaiC;
EC 2.7.11.1;
Gene name
kaiC

Comments [?]

case not <OC:Prochloraceae>
Function Core component of the KaiABC clock protein complex, which constitutes the main circadian regulator in cyanobacteria. Binds to DNA. The KaiABC complex may act as a promoter-nonspecific transcription regulator that represses transcription, possibly by acting on the state of chromosome compaction.
Catalytic activity RHEA:17989: ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein]
EC 2.7.11.1
RHEA:46608: ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein]
EC 2.7.11.1
Cofactor Mg(2+)
Activity regulation The interaction with KaiA enhances its phosphorylation status, while the interaction with KaiB decreases it. A KaiA dimer is sufficient to enhance KaiC phosphorylation.
Subunit Homohexamer; hexamerization is dependent on ATP-binding. Core component of the KaiABC complex, at least composed of a KaiC homohexamer, a KaiB dimer and two KaiA dimers. Interacts directly with SasA.
Domain The KaiC domains mediate the interaction with KaiA.
Ptm Phosphorylated on serine/threonine residues by autocatalysis. Both phosphorylated and unphosphorylated forms exist. Can probably autophosphorylate and autodephosphorylate. Phosphorylated form correlates with clock speed.
end case
case <OC:Prochloraceae>
Function Core component of the KaiBC clock protein complex, which constitutes the main circadian regulator in cyanobacteria. Binds to DNA. The KaiBC complex may act as a promoter-nonspecific transcription regulator that represses transcription, possibly by acting on the state of chromosome compaction.
Catalytic activity RHEA:17989: ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein]
EC 2.7.11.1
RHEA:46608: ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein]
EC 2.7.11.1
Cofactor Mg(2+)
Subunit Homohexamer; hexamerization is dependent on ATP-binding. Component of the KaiBC complex with KaiB. Interacts directly with SasA.
Ptm Phosphorylated on serine/threonine residues by autocatalysis. Both phosphorylated and unphosphorylated forms exist. Can probably autophosphorylate and autodephosphorylate. Phosphorylated form correlates with clock speed.
end case
Similarity Belongs to the KaiC family.

Keywords [?]

ATP-binding
Nucleotide-binding
Biological rhythms
DNA-binding
Magnesium
Metal-binding
Phosphoprotein
Repeat
Repressor
Kinase
Serine/threonine-protein kinase
Transcription
Transcription regulation
Transferase

Gene Ontology [?]

GO:0000287; Molecular function: magnesium ion binding.
GO:0004712; Molecular function: protein serine/threonine/tyrosine kinase activity.
GO:0005524; Molecular function: ATP binding.
GO:0007623; Biological process: circadian rhythm.

Cross-references [?]

Pfam PF06745; KaiC; 1;
TIGRFAMs TIGR02655; circ_KaiC; 1;

Features [?]

From: KAIC_SYNE7 (Q79PF4)
Key     From     To       Description   Tag   Condition   FTGroup
DOMAIN     72     180       KaiC 1        
DOMAIN     313     412       KaiC 2        
NP_BIND     46     53       ATP     G-x-[SAT]-G-x-G-K-[ST]  
NP_BIND     288     295       ATP     G-x-[SAT]-G-x-G-K-[ST]  
METAL     295     295       Magnesium     T  
METAL     318     318       Magnesium     E  
METAL     319     319       Magnesium     E  
METAL     378     378       Magnesium     D  
MOD_RES     432     432       Phosphothreonine; by autocatalysis     T  

Additional information [?]

Size range 499-541 amino acids
Related rules None
Fusion None
Comments Prochlorales do not contain the KaiA protein, which constitutes a regulator of KaiC, suggesting that regulation of circadian cycle is different in these bacteria.


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