FIGURE 6.

Molecular modeling of poly-Asp^86–93 peptide binding to {110} and {101} crystallographic faces of COD. Atomic configurations used for modeling at the surfaces of the {110} face (a) and {101} face (b) of COD. c–f, representative, top-scoring (low energy) models of poly-Asp^86–93 adsorbed onto COD. c and e, two lateral views (∼90° to each other) of poly-Asp^86–93 bound to a high calcium density plane in the {110} face of COD (with the N terminus of the peptide extending beyond the image plane in panel c, and with the N terminus of the peptide to the right in panel e. Some degree of lattice matching for five carboxylate (COO⁻) side chains aligned with calcium atoms occurs on the {110} face in this profile. d and f, two lateral views (∼90° to each other) of poly-Asp^86–93 bound to the {101} face of COD (with the N terminus of the peptide extending beyond the image plane in panel d and with the N terminus of the peptide to the right in panel f. Hydrogen bonding is schematically illustrated by dashed yellow lines connecting donor-acceptor pairs. Green, calcium; gray, carbon; red, oxygen; white, hydrogen).