Domain

EGF-like calcium-binding domain (IPR001881)

Short name: EGF-like_Ca-bd_dom

Domain relationships

None.

Description

A sequence of about forty amino-acid residues found in epidermal growth factor (EGF) has been shown [PMID: 2288911, PMID: 6334307, PMID: 3534958, PMID: 6607417, PMID: 3282918] to be present in a large number of membrane-bound and extracellular, mostly animal, proteins. Many of these proteins require calcium for their biological function and a calcium-binding site has been found at the N terminus of some EGF-like domains [PMID: 1527084]. Calcium-binding may be crucial for numerous protein-protein interactions.

For human coagulation factor IX it has been shown [PMID: 7606779] that the calcium-ligands form a pentagonal bipyramid. The first, third and fourth conserved negatively charged or polar residues are side chain ligands. The latter is possibly hydroxylated (see aspartic acid and asparagine hydroxylation site) [PMID: 1527084]. A conserved aromatic residue, as well as the second conserved negative residue, are thought to be involved in stabilising the calcium-binding site.

As in non-calcium binding EGF-like domains, there are six conserved cysteines and the structure of both types is very similar as calcium-binding induces only strictly local structural changes [PMID: 1527084].

                             +------------------+        +---------+
                             |                  |        |         |
               nxnnC-x(3,14)-C-x(3,7)-CxxbxxxxaxC-x(1,6)-C-x(8,13)-Cx
                   |                  | 
                   +------------------+

'n': negatively charged or polar residue [DEQN]
'b': possibly beta-hydroxylated residue [DN]
'a': aromatic amino acid
'C': cysteine, involved in disulphide bond
'x': any amino acid.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0005509 calcium ion binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
Pfam
SMART