EF hand

Introduction

Ca+2-binding domain consisting of a 12 residue loop flanked on both sides by a 12 residue alpha-helical domain. In an EF-hand loop, the Ca+2 is coordinated in a pentagonal bipyramidal configuration. Six residues are involved in Ca+2 binding. They are in positions 1, 3, 5, 7, 9 and 12. The invariant Glu or Asp at position 12 provides two oxygens for Ca+2-binding, thus the 7 coordinated ligands in a pentagonal bipyramidal configuration.

More general terms

• Ca+2-binding site