Figure 3. A schematic representation of the consensus secondary structure of a prototypical cbEGF-like domain. Calcium binding in the NH₂-terminal region of the wild-type domain is mediated by the highly conserved amino acids highlighted in blue. The highly conserved cysteines of the cbEGF-like domain are marked with a C, and the lines between the cysteine residues represent disulfide bridges. The mutation Cys790Ser affects the 4th cysteine residue, which is predicted to form a disulfide bridge with the 2nd cysteine residue (Cys776). The mutation abolishes the disulfide bond formation and thus causes misfolding of the protein.