 ExcaliburExcalibur calcium-binding domain | |
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| SMART ACC: | SM000894 |
| Description: | Extracellular Ca2+-dependent nuclease YokF from Bacillus subtilis and several other surface-exposed proteins from diverse bacteria are encoded in the genomes in two paralogous forms that differ by a ~45 amino acid fragment, which comprises a novel conserved domain. Sequence analysis of this domain revealed a conserved DxDxDGxxCE motif, which is strikingly similar to the Ca2+-binding loop of the calmodulin-like EF-hand domains, suggesting an evolutionary relationship between them. Functions of many of the other proteins in which the novel domain, named Excalibur (extracellular calcium-binding region), is found, as well as a structural model of its conserved motif are consistent with the notion that the Excalibur domain binds calcium. This domain is but one more example of the diversity of structural contexts surrounding the EF-hand-like calcium-binding loop in bacteria. This loop is thus more widespread than hitherto recognised and the evolution of EF-hand-like domains is probably more complex than previously appreciated. |
| InterPro ACC: | IPR008613 |
| InterPro abstract: | Extracellular Ca 2+ -dependent nuclease YokF from Bacillus subtilis and several other surface-exposed proteins from diverse bacteria are encoded in the genomes in two paralogous forms that differ by a ~45 amino acid fragment, which comprises a novel conserved domain. Sequence analysis of this domain revealed a conserved DxDxDGxxCE motif, which is strikingly similar to the Ca 2+ … expand |
| Family alignment: | View the Family alignment or the Alignment consensus sequence |
| There are 7 075 Excalibur domains in 6 914 proteins in SMART's NRDB database. | |
Taxonomic distribution of proteins containing Excalibur domains
The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing Excalibur domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.
Predicted cellular role
| Cellular role: | Interaction (with the environment) |
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Relevant references for this domain
Primary literature for the Excalibur 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 Excalibur domain which could be assigned to a KEGG orthologous group, and not all proteins containing Excalibur domains. Please note that proteins can be included in multiple pathways, ie. the numbers below will not add to 100%.