EF Hand

This is a helix-loop-helix, calcium-binding motif, in which two helices pack together at an angle of approximately 90 degrees, separated by a loop region, where calcium binds. The 'EF' notation for the motif resulted from the structure of parvalbumin, in which the 'E' and 'F' helices were originally identified to form this calcium-binding motif. The example shown is a human psoriasin (PDB code 1psr).

References

Carp muscle calcium-binding protein. II. Structure determination and general description.
Kretsinger RH, Nockolds CE
J Biol Chem248p3313-26(1973 May 10)
Evolution of the "EF-hand" family of calcium-binding proteins.
Perret C, Lomri N, Thomasset M
Adv Exp Med Biol269p17-20(1990)