EF hand domains

EF-hand domains comprise two helices that are arranged roughly perpendicular to each other and connected by a loop. Most EF-hand units are paired to form a compact lobe, and often bind calcium ions with ligands located in the loop that connects the helices.

EF-hand Ca(2+)-binding proteins participate both in modulation of calcium signals and in direct transduction of an ionic signal into downstream biochemical events. The biochemical repetoire of EF-hand proteins is correlated with differential response to conformational changes caused by Ca(2+) binding. For example, calmodulin and calbindin have homologous EF-hand domains, yet they respond to calcium binding differently.[pm]