Interaction between calcite and adsorptive peptide analyzed by fragment molecular orbital method

Calcite is a biomineral extensively studied as a typical example to elucidate the mechanism of biomineralization. It is known that the surface of calcite adsorbs Asp-rich peptides to initialize the biomineralization. However, understanding of the microscopic mechanism of the adsorption is still insufficient. We hence analyzed interaction energies based on the quantum mechanical calculation between calcite and Asp-rich peptides by using the fragment molecular orbital method. We quantitatively evaluated the importance of electrostatic interaction and the effect of charge transfer. Electrostatic interaction, not charge transfer, was found to be the main component of driving force for specific adsorption in calcite-DDGSDD.