Three-dimensional modeling of calcins. (A) Imperacalcin, resolved by ¹H-NMR (Lee et al., 2004), was taken as the template molecule. (B–H) Other calcins, including opicalcin₁ (B), opicalcin₂ (C), maurocalcin (D), hemicalcin (E), vejocalcin (F), urocalcin (G), and hadrucalcin (H), were simulated by Swiss-PdbViewer 4.1.0 and viewed by Discovery Studio 3.5. Solvent-accessible PSAs were calculated using PyMOL, whereas DMs were analyzed by the online Protein Dipole Moments Server. For each calcin, the solid ribbon with line atom model may be found in Fig. S1, and the charged CPK model with frontal side (middle) and dorsal side (right) are displayed here. Positively charged residues (Lys and Arg), negatively charged residues (Asp and Glu), and neutral residues are colored by blue, red, and gray, respectively.