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EF hand

EF hand
PDB 1osa EBI.jpg
Structure of the recombinant Paramecium tetraurelia calmodulin.
Identifiers
Symbol efhand
Pfam PF00036
InterPro IPR002048
PROSITE PDOC00018
SCOP 1osa
SUPERFAMILY 1osa
CDD cd00051

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.

Additional points:

Aequorin is a calcium binding protein (CaBP) isolated from the coelenterate Aequorea victoria. Aequorin belongs to the EF-hand family of CaBPs, with EF-hand loops that are closely related to CaBPs in mammals. In addition, aequorin has been used for years as an indicator of Ca2+ and has been shown to be safe and well tolerated by cells. Aequorin is made up of two components – the calcium binding component apoaequorin (AQ) and the chemiluminescent molecule coelenterazine. The AQ portion of this protein contains the EF-hand calcium binding domains.

Humans proteins containing this domain include:


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