FIGURE 4.

Overlay of WT-CBD1 and CBD2 demonstrating the conserved Ca²⁺ binding sites. WT-CBD1 is shown as a blue drawing with Ca²⁺ ions depicted as blue spheres. CBD2 (PDB code: 2QVM) is represented as a red drawing with the primary (I) and secondary (II)Ca²⁺ ions depicted as red spheres (r.m.s.d. = 1.1 Å over 112 Cα). The CBD2 primary Ca²⁺ binding site is at a position homologous to Ca²⁺ ions 3 and 4 of CBD1. For clarity, the strands are labeled A–G.