| EF hand | |||||||||
|---|---|---|---|---|---|---|---|---|---|
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| Identifiers | |||||||||
| Symbol | efhand | ||||||||
| Pfam | PF00036 | ||||||||
| Pfam clan | CL0220 | ||||||||
| ECOD | 108.1.1 | ||||||||
| InterPro | IPR002048 | ||||||||
| PROSITE | PDOC00018 | ||||||||
| SCOP2 | 1osa / SCOPe / SUPFAM | ||||||||
| CDD | cd00051 | ||||||||
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The EF hand is a helix–loop–helix structural domain or motif found in a large family of calcium-binding proteins.
The EF-hand motif contains a helix–loop–helix topology, much like the spread thumb and forefinger of the human hand, in which the Ca2+ ions are coordinated by ligands within the loop. The motif takes its name from traditional nomenclature used in describing the protein parvalbumin, which contains three such motifs and is probably involved in muscle relaxation via its calcium-binding activity.
The EF-hand consists of two alpha helices linked by a short loop region (usually about 12 amino acids) that usually binds calcium ions. EF-hands also appear in each structural domain of the signaling protein calmodulin and in the muscle protein troponin-C.
- ^ Ban C, Ramakrishnan B, Ling KY, Kung C, Sundaralingam M (January 1994). "Structure of the recombinant Paramecium tetraurelia calmodulin at 1.68 A resolution". Acta Crystallogr. D. 50 (Pt 1): 50–63. doi:10.1107/S0907444993007991. PMID 15299476.