EF-hand motifs

EF-hand motifs are specialized structural elements found in certain proteins that help them bind calcium ions. They are shaped like a hand with a loop (the "EF-hand") that coordinates and holds calcium tightly. When calcium binds to this loop, it causes the protein to change shape, which can activate or modify its function in processes like muscle contraction, signal transmission, or cell regulation. These motifs are common in many calcium-binding proteins and are essential for translating calcium signals into cellular responses.