Summary: KaiB domain

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Wikipedia: Cyanobacterial clock proteins
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Cyanobacterial clock proteins Edit Wikipedia article

KaiA domain

crystal structure of circadian clock protein kaia from synechococcus elongatus

Identifiers

Symbol

KaiA

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

KaiB domain

solution structure of the n-terminal domain of synechococcus elongatus sasa (average minimized structure)

Identifiers

Symbol

KaiB

Pfam clan

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

KaiC

crystal structure of full length circadian clock protein kaic with phosphorylation sites

Identifiers

Symbol

KaiC

Pfam clan

Available protein structures:
Pfam	structures
PDB	RCSB PDB; PDBe
PDBsum	structure summary

In molecular biology, the cyanobacterial clock proteins are the main circadian regulator in cyanobacteria. The cyanobacterial clock proteins comprise three proteins: kiaA, kiaB and kiaC. The kaiABC complex may act as a promoter-nonspecific transcription regulator that represses transcription, possibly by acting on the state of chromosome compaction.

In the complex, KaiA enhances the phosphorylation status of kaiC. In contrast, the presence of kaiB in the complex decreases the phosphorylation status of kaiC, suggesting that kaiB acts by antagonising the interaction between kaiA and kaiC. The activity of KaiA activates kaiBC expression, while KaiC represses it. The overall fold of the KaiA monomer is that of a four-helix bundle, which forms a dimer in the known structure.^[1] KaiA functions as a homodimer. Each monomer is composed of three functional domains: the N-terminal amplitude-amplifier domain, the central period-adjuster domain and the C-terminal clock-oscillator domain. The N-terminal domain of KaiA, from cyanobacteria, acts as a pseudo-receiver domain, but lacks the conserved aspartyl residue required for phosphotransfer in response regulators.^[2] The C-terminal domain is responsible for dimer formation, binding to KaiC, enhancing KaiC phosphorylation and generating the circadian oscillations.^[3] The KaiA protein from Anabaena sp. (strain PCC 7120) lacks the N-terminal CheY-like domain.

KaiB adopts an alpha-beta meander motif and is found to be a dimer or a tetramer.^[1]^[4]

KaiC belongs to a larger family of proteins; it performs autophosphorylation and acts as its own transcriptional repressor. It binds ATP.^[5]

Also in the KiaC family is RadA/Sms, a highly conserved eubacterial protein that shares sequence similarity with both RecA strand transferase and lon protease. The RadA/Sms family are probable ATP-dependent proteases involved in both DNA repair and degradation of proteins, peptides, glycopeptides. They are classified in as non-peptidase homologues and unassigned peptidases in MEROPS peptidase family S16 (lon protease family, clan SJ). RadA/Sms is involved in recombination and recombinational repair, most likely involving the stabilisation or processing of branched DNA molecules or blocked replication forks because of its genetic redundancy with RecG and RuvABC.^[6]

[edit] References

^ ^a ^b Garces RG, Wu N, Gillon W, Pai EF (April 2004). "Anabaena circadian clock proteins KaiA and KaiB reveal a potential common binding site to their partner KaiC". EMBO J. 23 (8): 1688â98. doi:10.1038/sj.emboj.7600190. PMC 394244. PMID 15071498. //www.ncbi.nlm.nih.gov/pmc/articles/PMC394244/.
^ Williams SB, Vakonakis I, Golden SS, LiWang AC (November 2002). "Structure and function from the circadian clock protein KaiA of Synechococcus elongatus: a potential clock input mechanism". Proc. Natl. Acad. Sci. U.S.A. 99 (24): 15357â62. doi:10.1073/pnas.232517099. PMC 137721. PMID 12438647. //www.ncbi.nlm.nih.gov/pmc/articles/PMC137721/.
^ Uzumaki T, Fujita M, Nakatsu T, Hayashi F, Shibata H, Itoh N, Kato H, Ishiura M (July 2004). "Crystal structure of the C-terminal clock-oscillator domain of the cyanobacterial KaiA protein". Nat. Struct. Mol. Biol. 11 (7): 623â31. doi:10.1038/nsmb781. PMID 15170179.
^ Hitomi K, Oyama T, Han S, Arvai AS, Getzoff ED (2005). "Tetrameric architecture of the circadian clock protein KaiB. A novel interface for intermolecular interactions and its impact on the circadian rhythm.". J Biol Chem 280 (19): 19127â35. doi:10.1074/jbc.M411284200. PMID 15716274. http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15716274.
^ Pattanayek R, Wang J, Mori T, Xu Y, Johnson CH, Egli M (2004). "Visualizing a circadian clock protein: crystal structure of KaiC and functional insights.". Mol Cell 15 (3): 375â88. doi:10.1016/j.molcel.2004.07.013. PMID 15304218. http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15304218.
^ Beam CE, Saveson CJ, Lovett ST (December 2002). "Role for radA/sms in recombination intermediate processing in Escherichia coli". J. Bacteriol. 184 (24): 6836â44. PMC 135464. PMID 12446634. //www.ncbi.nlm.nih.gov/pmc/articles/PMC135464/.

This article incorporates text from the public domain Pfam and InterPro IPR011648

This article incorporates text from the public domain Pfam and InterPro IPR011649

This article incorporates text from the public domain Pfam and InterPro IPR014774

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

KaiB domain Provide feedback

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 [1].

Literature references

Garces RG, Wu N, Gillon W, Pai EF; , EMBO J 2004;23:1688-1698.: Anabaena circadian clock proteins KaiA and KaiB reveal a potential common binding site to their partner KaiC. PUBMED:15071498 EPMC:15071498

External database links

PANDIT:	PF07689
Pseudofam:	PF07689
SYSTERS:	KaiB

This tab holds annotation information from the InterPro database.

InterPro entry IPR011649

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 [PUBMED:15071498].

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Biological process

rhythmic process (GO:0048511)

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan Thioredoxin (CL0172), which contains the following 45 members:

2Fe-2S_thioredx AhpC-TSA AhpC-TSA_2 ArsC ArsD Calsequestrin DIM1 DSBA DUF1525 DUF1687 DUF2703 DUF4174 DUF836 DUF899 DUF953 ERp29_N Glutaredoxin GSHPx GST_N GST_N_2 GST_N_3 HyaE KaiB MRP-S23 MRP-S25 OST3_OST6 Phosducin Redoxin SCO1-SenC SelP_N SH3BGR T4_deiodinase Thioredox_DsbH Thioredoxin Thioredoxin_2 Thioredoxin_3 Thioredoxin_4 Thioredoxin_5 Thioredoxin_6 Thioredoxin_7 Thioredoxin_8 Thioredoxin_9 Tom37 TraF YtfJ_HI0045

Alignments

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...

There are various ways to view or download the sequence alignments that we store. We provide several sequence viewers and a plain-text Stockholm-format file for download.

Alignment types

We make a range of alignments for each Pfam-A family:

seed: the curated alignment from which the HMM for the family is built
full: the alignment generated by searching the sequence database using the HMM
RP15/RP35/RP55/RP75: Representative Proteomes (RPs) at 15%, 35%, 55% and 75% co-membership thresholds
NCBI: alignment generated by searching the NCBI sequence database using the family HMM
meta: alignment generated by searching the metagenomics sequence database using the family HMM

Viewing

You can see the alignments as HTML or in three different sequence viewers:

jalview: a Java applet developed at the University of Dundee. You will need Java installed before running jalview
HTML: an HTML page showing the whole alignment.Please note: full Pfam alignments can be very large. These HTML views are extremely large and often cause problems for browsers. Please use either jalview or the Pfam viewer if you have trouble viewing the HTML version
PP/Heatmap: an HTML-based representation of the alignment, coloured according to the posterior-probability (PP) values from the HMM. As for the standard HTML view, heatmap alignments can also be very large and slow to render.
Pfam viewer: an HTML-based viewer that uses DAS to retrieve alignment fragments on request

Reformatting

You can download (or view in your browser) a text representation of a Pfam alignment in various formats:

Selex
Stockholm
FASTA
MSF

You can also change the order in which sequences are listed in the alignment, change how insertions are represented, alter the characters that are used to represent gaps in sequences and, finally, choose whether to download the alignment or to view it in your browser directly.

Downloading

You may find that large alignments cause problems for the viewers and the reformatting tool, so we also provide all alignments in Stockholm format. You can download either the plain text alignment, or a gzipped version of it.

View options

We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

	Seed (16)	Full (352)	Representative proteomes				NCBI (572)	Meta (244)
	Seed (16)	Full (352)	RP15 (31)	RP35 (86)	RP55 (113)	RP75 (129)	NCBI (572)	Meta (244)
Jalview	View	View	View	View	View	View	View	View
HTML	View	View	View	View	View	View
PP/heatmap	₁	View	View	View	View	View
Pfam viewer	View	View

¹Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: available, not generated, — not available.

Format an alignment

	Seed (16)	Full (352)	Representative proteomes				NCBI (572)	Meta (244)
	Seed (16)	Full (352)	RP15 (31)	RP35 (86)	RP55 (113)	RP75 (129)	NCBI (572)	Meta (244)
Alignment:
Format:
Order:	Tree Alphabetical
Sequence:	Inserts lower case All upper case
Gaps:
Download/view:	Download View

Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

	Seed (16)	Full (352)	Representative proteomes				NCBI (572)	Meta (244)
	Seed (16)	Full (352)	RP15 (31)	RP35 (86)	RP55 (113)	RP75 (129)	NCBI (572)	Meta (244)
Raw Stockholm	Download	Download	Download	Download	Download	Download	Download	Download
Gzipped	Download	Download	Download	Download	Download	Download	Download	Download

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

External links

MyHits provides a collection of tools to handle multiple sequence alignments. For example, one can refine a seed alignment (sequence addition or removal, re-alignment or manual edition) and then search databases for remote homologs using HMMER3.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation

Seed source:

Bateman A

Previous IDs:

none

Type:

Domain

Author:

Bateman A

Number in seed:

16

Number in full:

352

Average length of the domain:

80.00 aa

Average identity of full alignment:

41 %

Average coverage of the sequence by the domain:

45.47 %

HMM information

HMM build commands:

build method: hmmbuild -o /dev/null HMM SEED

search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq

Model details:

Parameter	Sequence	Domain
Gathering cut-off	20.4	20.4
Trusted cut-off	20.4	20.4
Noise cut-off	20.3	20.3

Model length:

82

Family (HMM) version:

7

Download:

download the raw HMM for this family

Species distribution

Sunburst
Tree

Sunburst controls

Show

This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

This chart is a modified "sunburst" visualisation of the species tree for this family. It shows each node in the tree as a separate arc, arranged radially with the superkingdoms at the centre and the species arrayed around the outermost ring.

How the sunburst is generated

The tree is built by considering the taxonomic lineage of each sequence that has a match to this family. For each node in the resulting tree, we draw an arc in the sunburst. The radius of the arc, its distance from the root node at the centre of the sunburst, shows the taxonomic level ("superkingdom", "kingdom", etc). The length of the arc represents either the number of sequences represented at a given level, or the number of species that are found beneath the node in the tree. The weighting scheme can be changed using the sunburst controls.

In order to reduce the complexity of the representation, we reduce the number of taxonomic levels that we show. We consider only the following eight major taxonomic levels:

superkingdom
kingdom
phylum
class
order
family
genus
species

Colouring and labels

Segments of the tree are coloured approximately according to their superkingdom. For example, archeal branches are coloured with shades of orange, eukaryotes in shades of purple, etc. The colour assignments are shown under the sunburst controls. Where space allows, the name of the taxonomic level will be written on the arc itself.

As you move your mouse across the sunburst, the current node will be highlighted. In the top section of the controls panel we show a summary of the lineage of the currently highlighed node. If you pause over an arc, a tooltip will be shown, giving the name of the taxonomic level in the title and a summary of the number of sequences and species below that node in the tree.

Anomalies in the taxonomy tree

There are some situations that the sunburst tree cannot easily handle and for which we have work-arounds in place.

Missing taxonomic levels

Some species in the taxonomic tree may not have one or more of the main eight levels that we display. For example, Bos taurus is not assigned an order in the NCBI taxonomic tree. In such cases we mark the omitted level with, for example, "No order", in both the tooltip and the lineage summary.

Unmapped species names

The tree is built by looking at each sequence in the full alignment for the family. We take the name of the species given by UniProt and try to map that to the full taxonomic tree from NCBI. In some cases, the name chosen by UniProt does not map to any node in the NCBI tree, perhaps because the chosen name is listed as a synonym or a misspelling in the NCBI taxonomy.

So that these nodes are not simply omitted from the sunburst tree, we group them together in a separate branch (or segment of the sunburst tree). Since we cannot determine the lineage for these unmapped species, we show all levels between the superkingdom and the species as "uncategorised".

Sub-species

Since we reduce the species tree to only the eight main taxonomic levels, sequences that are mapped to the sub-species level in the tree would not normally be shown. Rather than leave out these species, we map them instead to their parent species. So, for example, for sequences belonging to one of the Vibrio cholerae sub-species in the NCBI taxonomy, we show them instead as belonging to the species Vibrio cholerae.

Too many species/sequences

For large species trees, you may see blank regions in the outer layers of the sunburst. These occur when there are large numbers of arcs to be drawn in a small space. If an arc is less than approximately one pixel wide, it will not be drawn and the space will be left blank. You may still be able to get some information about the species in that region by moving your mouse across the area, but since each arc will be very small, it will be difficult to accurately locate a particular species.

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Tree controls

Hide

The tree shows the occurrence of this domain across different species. More...

Species trees

We show the species tree in one of two ways. For smaller trees we try to show an interactive representation, which allows you to select specific nodes in the tree and view them as an alignment or as a set of Pfam domain graphics.

Unfortunately we have found that there are problems viewing the interactive tree when the it becomes larger than a certain limit. Furthermore, we have found that Internet Explorer can become unresponsive when viewing some trees, regardless of their size. We therefore show a text representation of the species tree when the size is above a certain limit or if you are using Internet Explorer to view the site.

If you are using IE you can still load the interactive tree by clicking the "Generate interactive tree" button, but please be aware of the potential problems that the interactive species tree can cause.

Interactive tree

For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.

We also count the number of unique sequences on which each domain is found, which is shown in green. Note that a domain may appear multiple times on the same sequence, leading to the difference between these two numbers.

Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.

We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.

You can use the tree controls to manipulate how the interactive tree is displayed:

show/hide the summary boxes
highlight species that are represented in the seed alignment
expand/collapse the tree or expand it to a given depth
select a sub-tree or a set of species within the tree and view them graphically or as an alignment
save a plain text representation of the tree

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Interactions

There is 1 interaction for this family. More...

KaiB

Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the KaiB domain has been found. There are 18 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

Loading structure mapping...

Archea	Eukaryota
Bacteria	Other sequences
Viruses	Unclassified
Viroids	Unclassified sequence

Family: KaiB (PF07689)

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Summary: KaiB domain

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Cyanobacterial clock proteins Edit Wikipedia article

[edit] References

KaiB domain Provide feedback

Literature references

External database links

InterPro entry IPR011649

Gene Ontology

Domain organisation

Pfam Clan

Alignments

Alignment types

Viewing

Reformatting

Downloading

View options

Format an alignment

Download options

External links

HMM logo

Trees

Curation and family details

Curation

HMM information

Species distribution

Sunburst controls

Weight segments by...

Change the size of the sunburst

Colour assignments

Selections

Currently selected:

How the sunburst is generated

Colouring and labels

Anomalies in the taxonomy tree

Missing taxonomic levels

Unmapped species names

Sub-species

Too many species/sequences

Tree controls

Annotation

Download tree

Selected sequences

Species trees

Interactive tree

Interactions

Structures