Evolutionary Selection of Bone Mineral Hydroxyapatite Binding Peptides Using Landscape Phage Library

摘要

The goal of this work is to identify a peptide that can specifically bind bone mineral hydroxyapatite [(Ca5(PO4)3OH)2] from a phage-displayed random peptide library. Instead of using pill library where random peptides are displayed at the tip of filamentous phage, we used landscape phage libraries, in which random octa-peptides or nona-peptides are displayed on all the N-termini of the pVIlI (major coat protein) of the tetracycline resistant phage (fd-tet) The crystalline hydroxyapatite (HA) powder was used as a target during biopanning. We selected clones that bind with high affinity to HA. Three 8-mer and two 9-mer peptides were found to bind to HA with high affinity The motif alignments showed that the selected binding peptides share common motifs with proteins found in bone including collagen, biglycan, osteocalcin, and osteonectin. Our results indicate that both collagen and non-collagenous proteins can contribute to HA binding during bone formation