KaiB
SMART ACC:	SM001248
Description:	The cyanobacterial clock proteins KaiA and KaiB are proposed as regulators of the circadian rhythm in cyanobacteria. Mutations in both proteins have been reported to alter or abolish circadian rhythmicity. KaiB adopts an alpha-beta meander motif and is found to be a dimer (PMID: 15071498).
InterPro ACC:	IPR011649
InterPro abstract:	The cyanobacterial clock proteins KaiA, KaiB and SasA are proposed as regulators of the circadian rhythm in cyanobacteria [ PUBMED:12441347 PUBMED:12727878 ]. Mutations in both proteins have been reported to alter or abolish circadian rhythmicity. … expand The cyanobacterial clock proteins KaiA, KaiB and SasA are proposed as regulators of the circadian rhythm in cyanobacteria [ PUBMED:12441347 PUBMED:12727878 ]. Mutations in both proteins have been reported to alter or abolish circadian rhythmicity. KaiB adopts an α-β meander motif and is found to be a dimer [ PUBMED:15313603 ]. KaiB was originally discovered from the cyanobacterium Synechococcus as part of the circadian clock gene cluster, kaiABC. KaiB attenuates KaiA-enhanced KaiC autokinase activity by interacting with KaiA-KaiC complexes in a circadian fashion [ PUBMED:15071498 PUBMED:12727879 ]. KaiB is membrane-associated as well as cytosolic. The amount of membrane-associated protein peaks in the evening (at circadian time (CT) 12-16) while the cytosolic form peaks later (at CT 20). The rhythmic localisation of KaiB may function in regulating the formation of Kai complexes. SasA is a sensory histidine kinase which associates with KaiC [ PUBMED:10786837 ]. Although it is not an essential oscillator component, it is important in enhancing kaiABC expression and is important in metabolic growth control under day/night cycle conditions. SasA contains an N-terminal sensory domain with a TRX fold which is involved in the SasA-KaiC interaction [ PUBMED:12449424 ]. This domain shows high sequence similarity with KaiB [ PUBMED:15014139 ]. However, the KaiB structure does not show a classical TRX fold. The N-terminal half of KaiB shares the same β-α-β topology as TRX, but the topology of its C-terminal half diverges. collapse
GO process:	rhythmic process (GO:0048511)
Family alignment:	View the Family alignment or the Alignment consensus sequence
There are 1 766 KaiB domains in 1 766 proteins in SMART's NRDB database.

Taxonomic distribution of proteins containing KaiB domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing KaiB domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Relevant references for this domain

Primary literature for the KaiB domain is listed below. Automatically-derived, secondary literature is also available.

KEGG pathways involving proteins which contain this domain

This information is based on the mapping of SMART genomic protein database to KEGG orthologous groups. Percentages are related to the number of proteins containing a KaiB domain which could be assigned to a KEGG orthologous group, and not all proteins containing KaiB domains. Please note that proteins can be included in multiple pathways, ie. the numbers below will not add to 100%.

KEGG pathways

KEGG orthologous groups

3D structures in PDB containing this domain

Links to other resources describing this domain

InterPro	IPR011649
Pfam	KaiB