In a typical EF-hand, six residues are necessary for the coordination of the calcium ion. These are labeled as the X, Y, Z, −Y, −X and −Z residues, and consensus residues at these positions have been identified . Residues Asp46, Asp48, Ser50, Val52, Thr54 and Glu57 were predicted as constituting a potential calcium-binding site in the EF-hand of CsTegu20.6 using COACH  (Figure 6). The consensus is mostly observed, with a different residue, Val52, at the −Y residue, which is rarely observed at this position. The orientation of the Val52 side chain is also more distant from the calcium-binding site compared to that of the Thr52 side chain in a typical EF-hand. Therefore, it is improbable that this EF-hand contacts calcium ions.