InterPro domain: IPR011992

This domain superfamily consists of a duplication of two EF-hand units, where each unit is composed of two helices connected by a twelve-residue calcium-binding loop. The calcium ion in the EF-hand loop is coordinated in a pentagonal bipyramidal configuration. Many calcium-binding proteins contain an EF-hand type calcium-binding domain [ 1 , 2 ]. These include: calbindin D9K, S100 proteins such as calcyclin, polcalcin phl p 7 (a calcium-binding pollen allergen), osteonectin, parvalbumin, calmodulin [ 3 ] family of proteins (troponin C, caltractin, cdc4p, myosin essential chain, calcineurin, recoverin, neurocalcin), plasmodial-specific CaII-binding protein Cbp40, penta-EF-Hand proteins [ 4 ] (sorcin, grancalcin, calpain), as well as multidomain proteins such as phosphoinositide-specific phospholipase C, dystrophin, Cb1 and alpha-actinin. The fold consists of four helices and an open array of two hairpins.

1. The role of calcium-binding proteins in the control of transcription: structure to function. Bioessays 24, 625-36
2. EF-hand calcium-binding proteins. Curr. Opin. Struct. Biol. 10, 637-43
3. Novel aspects of calmodulin target recognition and activation. Eur. J. Biochem. 270, 404-14
4. Structures, functions and molecular evolution of the penta-EF-hand Ca2+-binding proteins. Biochim. Biophys. Acta 1600, 51-60