Conserved Protein Domain Family

pfam05901: Excalibur 
Excalibur calcium-binding domain
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 recognized and the evolution of EF-hand-like domains is probably more complex than previously appreciated.
PSSM-Id: 399117
Aligned: 142 rows
Threshold Bit Score: 30.1272
Threshold Setting Gi: 269786990
Created: 21-May-2020
Updated: 7-Aug-2020
Aligned Rows:
PubMed ReferencesClick to see Conserved Features Help

Sequence Alignment
Format: Row Display: Color Bits: Type Selection:
5J8T_A             9 FSSCKEAWANGYsdihegEPGY-------S---AKLDRDHDGVACE 44 
DU:RAM_00850      30 DLDCKNFQYQEE------AQAVld---atPgdpNDLDRDKNGIACE 66  Amycolatopsis mediterranei S699
AORICAS:Z0000164  37 DLDCGDFKYQEE------AQAEle---kdRsdpHGLDRDKDGIACE 73  Amycolatopsis keratiniphila
jgi:RoseRS_4309  409 DKDCSDFSTQAE------AQAFflanggpDrdpHRLDGDNDGIACE 448 Roseiflexus sp. RS-1
WP_012813886     181 DKDCSDFSTQGQ------AQRFfea--hqPgdpHRLDGDGDGQVCE 218 Desulfohalobium retbaense
jgi:Celf_3570    289 avDCRDFATWAE------ADAWfrtyepyYgdvAELDGNDDGEACE 328 Cellulomonas fimi ATCC 484
tigr:AAur_3212   378 TKNCTDFATWRQ------AQDWfnyyfpwYgdvAGLDSDGDRIACE 417 Paenarthrobacter aurescens TC1
EHR53075          29 DKDCGDFATQQE------AMEAheq--ldPedaWELDRDKDGKPCE 66  Saccharomonospora marina XMU15
jgi:Sthe_1699     29 rvTCSDFPSQAA------AQAAyr---adPiglSNLDQDKDGIACE 65  Sphaerobacter thermophilus DSM 20745
WP_093936405      58 DKDCADFPSQAA------AQAElk---knPrdpHRLDGDHDGYACE 94  Amycolatopsis thailandensis
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