抄録
Hydroxyapatite (HA) is a major component of bone and teeth. It has been proposed that octacalcium phosphate (OCP) and/or amorphous calcium phosphate are precursors of HA, and its evolution is regulated by specific proteins. Understanding the mechanisms by which biomolecules regulate the mineralization of calcium phosphates will provide guiding principles for fabricating biomaterials with properties similar to those of biological apatite. Dentin matrix protein 1 (DMP1) is the protein involved in bone and dentin mineralization. Synthetic peptides analogous to DMP1 motifs A and B have been shown to accelerate HA formation when they were immobilized on a glass surface. We have previously constructed artificial proteins by combinatorially assembling these two motifs, and found that one of the created proteins, namely, #64, accelerated HAP and OCP formation without immobilization. In this report, we investigated the effects of #64 derivatives on the crystal morphologies of calcium phosphates in mineralization experiments. Four #64 mutants, containing motifs in which the acidic residues were substituted with neutral residues, showed different levels of mineralization activity, and the resultant calcium phosphate precipitates had distinct morphologies, indicating a possible evolutionary path of calcium phosphates precipitated in the presence of motif-programmed artificial proteins.
