Nucleation and growth inhibition of biological minerals by cementum attachment protein-derived peptide (CAP-pi).

Biomineralization is a highly regulated process where proteins/peptides-crystal interactions contribute to the shaping, phasing and aggregation of minerals. We have identified and synthesized a cementum attachment protein-derived peptide (CAP-pi), which corresponds to amino acids 40-53 of the N-terminal CAP domain (MASSDEDGTNGGAS) and its phosphorylated variant (MASpSpDEDGTNGGASp) (CAP-pip). The peptide is composed of polar and negatively charged amino acids, which are disordered, according to in silico analysis. Our results show that CAP-pi inhibits hydroxyapatite (HA) formation and growth. However, it possesses low capacity to inhibit calcium oxalate crystal growth. CAP-pip showed a stronger inhibitory effect on the formation and growth of HA. As well as a high capacity to inhibit calcium oxalate monohydrate growth, mainly due to adsorption on specific growth faces. Small peptides have many advantages over the full-size protein, including low-cost production and modulation characteristics that allow for structural changes. Our findings suggest that CAP-pip-derived peptide could possess therapeutic potential to prevent or treat pathological calcifications such as renal stones and vascular calcification.