2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Clean Technology 2008

Evolutionary selection of bone mineral hydroxyapatite binding peptide using landscape phage library

S. Modali, G. Abbineni, P. Jayanna, V. Petrenko, C. Mao
University of Oklahoma, US

Keywords:
bone, phage, hydroxyapatite

Abstract:
Hydroxyapatite [(Ca5(PO4)3OH)2] is a biomineral which is associated with bone proteins to form mineralized extracellular matrix in a mature bone. Using two landscape phage libraries, in which random octa-peptides and nona-peptides are displayed on all the N-termini of the pVIII (major coat protein) of the tetracycline resistant phage (fd-tet), we selected clones that bind with high affinity to crystalline hydroxyapatite (HA). A HA column was used as a target and treated with the landscape phage libraries during biopanning. The HA column was washed with step gradient elution with phosphate buffered saline (PBS), during which the weak and strong binders were eluted at low and high concentrations of phosphate, respectively. The selected phage clones were bound preferentially to HA when compared to other phages. Binding assay was used to assess the selectivity and specificity with which these peptides bind to HA. The motif alignments showed that the selected binding peptides share motifs with bone proteins including collagen, biglycan, osteocalcin, and osteopontin. In bone biomineralization, which proteins are associated with HA binding and nucleation is still controversial. Thus our results shed light on the mechanism of bone biomineralization.


Nanotech 2008 Conference Program Abstract