Unusual binding of barium to the EF-hand 2 of EhCaBP1. Barium has dual, partial occupancy to the EF hand 2 motif. (A) Barium coordinates with seven ligands from the protein to satisfy the coordination geometry. The coordination distances are shown. (B) Another barium ion in the close vicinity of EF-hand 2 motif is coordinated with the backbone oxygen atoms of K43, D46 and D48 residues of the protein and with two water molecules. The coordination distances between the barium ion and oxygen atoms range between 2.7 Ǻ and 3.4 Ǻ.
Kumar et al. BMC Biophysics 2012 5:15 doi:10.1186/2046-1682-5-15