Binding of Bone Sialoprotein, Osteopontin and Synthetic Polypeptides to Hydroxyapatite

Goldberg, Harvey A.; Warner, Kevin J.; Li, Michael C.; Hunter, Graeme

doi:10.3109/03008200109014246

Cited by 123 publications

(126 citation statements)

References 39 publications

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“…This notion is supported by HA binding studies, which have shown that BSP binds to HA, at least in part, via the contiguous poly[E] sequences. Synthetic homopolymers of poly[E], however, did not completely inhibit this binding (48). It was therefore suggested that additional domain(s), or specific conformational motifs on BSP, are involved in HA binding and perhaps in HA nucleation.…”

Section: Discussionmentioning

confidence: 99%

Delineation of the Hydroxyapatite-nucleating Domains of Bone Sialoprotein

Tye

Rattray

Warner

et al. 2003

Journal of Biological Chemistry

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198

181

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Bone sialoprotein (BSP) is a highly modified, anionic phosphoprotein that is expressed almost exclusively in mineralizing connective tissues and has been shown to be a potent nucleator of hydroxyapatite (HA). Two polyglutamic acid (poly[E]) regions, predicted to be in an ␣-helical conformation and located in the amino-terminal half of the molecule, are believed to be responsible for this activity. Using a prokaryotic expression system, full-length rat BSP was expressed and tested for HA nucleating activity in a steady-state agarose gel system. The unmodified protein is less potent than native bone BSP, indicating a role for the post-translational modifications in HA nucleation. domains, were expressed and tested for nucleating activity. Whereas the peptide encompassing the second poly[E] domain was capable of nucleating HA, the first domain peptide showed no activity. The conformation of the wild-type and mutated proteins and peptides were studied by circular dichroism and small angle x-ray scattering, and no secondary structure was evident. These results demonstrate that a sequence of at least eight contiguous glutamic acid residues is required for the nucleation of HA by BSP and that this nucleating "site" is not ␣-helical in conformation.Mineralization of the extracellular matrix in bone, dentin, and cementum is a complex, poorly understood process that is believed to involve both hydroxyapatite-nucleating and -modulating noncollagenous proteins. In bone, it has been postulated that type I collagen acts as a structural matrix, whereas HA nucleation is mediated by an anionic phosphoprotein (1-3). Of the noncollagenous proteins, bone sialoprotein (BSP) 1 is the most likely candidate. The highly anionic nature of BSP and its spatio-temporal pattern of expression have led investigators to propose a role of this protein in the mineralization of bone (1-4).Mammalian BSPs contain an average of 327 amino acids, which includes a 16-residue signal sequence. The protein has a molecular mass of ϳ33-34 kDa. However, post-translational modifications, including both N-and O-linked glycosylation, tyrosine sulfation, and serine and threonine phosphorylation, constitute 50% of the total mature protein weight of ϳ75 kDa. Analysis of the mammalian BSP cDNAs reveals a 45% level of sequence identity, plus an additional 10 -23% in conservative replacements. However, identity of up to 90% is observed in and around two polyglutamic acid sequences (poly[E]); an ArgGly-Asp (RGD) cell-binding motif; sites of phosphorylation, sulfation, and glycosylation; and sequences near the amino and carboxyl termini, which are rich in tyrosine residues (5).Normally BSP expression is limited almost exclusively to mineralized connective tissues, and its expression is localized to areas of bone formation. By in situ hybridization, it has been shown that BSP expression occurs in osteoblasts actively engaged in bone formation and is found at low or undetectable levels in other regions of mineralized tissue (6 -11). Transfection of BSP into nonmineralizin...

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Section: Discussionmentioning

confidence: 99%

Delineation of the Hydroxyapatite-nucleating Domains of Bone Sialoprotein

Tye

Rattray

Warner

et al. 2003

Journal of Biological Chemistry

Self Cite

198

181

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“…Several studies have examined the adsorption characteristics of proteins or peptides to HAP or other calcium phosphate surfaces, primarily with a focus on understanding the mineralization induction or inhibition abilities of that particular protein. [7][8][9] Recently, Krout et al examined the influence that osteocalcin (OC) has on both the mineral structure and cell binding properties when it is included as a component of the mineralization solution. It was found that while there were no changes to the crystal properties, there was improved cellular adhesion to the samples through the incorporation of OC within the sample.…”

Section: Introductionmentioning

confidence: 99%

MC3T3-E1 cell adhesion to hydroxyapatite with adsorbed bone sialoprotein, bone osteopontin, and bovine serum albumin

Bernards

Qin

Jiang

2008

Colloids and Surfaces B: Biointerfaces

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Native bone tissue is composed of a complex matrix of collagen, non-collagenous proteins, and hydroxyapatite (HAP). Bone sialoprotein (BSP) and bone osteopontin (OPN) are members of the non-collagenous protein family termed the SIBLING (small integrin-binding ligand, N-linked glycoproteins) proteins, which are primarily found in mineralized tissues. Previously, OPN was shown to exhibit a preferential orientation for MC3T3-E1 cell adhesion when it was specifically bound to collagen, while the MC3T3-E1 cell adhesion was shown to be dependant on the conformational flexibility of BSP specifically bound to collagen. Additionally, OPN was shown to play a greater role than BSP for cell binding to collagen. In this work, the orientations and conformations of BSP and OPN specifically bound to HAP are probed under similar conditions. Radiolabeled adsorption isotherms were obtained for BSP and OPN on HAP formed from a simulated body fluid, and the results show that HAP has the capacity to bind significantly more BSP than OPN. An in vitro MC3T3-E1 cell adhesion assay was then performed to compare the cell binding ability of adsorbed BSP and OPN specifically bound to HAP. It was found that there is a preference for cell binding to HAP with adsorbed BSP as compared to OPN, but not to a statistically significant level. However, the maximum cell binding was observed on HAP substrates with adsorbed heat denatured bovine serum albumin (BSA). The influence of BSA on cell binding was shown to be concentration dependant and it is believed that the adsorbed BSA modulates the proliferation state of the bound cells.

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“…Therefore, biological templated mineralization could be employed to synthesize bone mimetic materials. This process is thought to occur by binding the acidic groups of peptides with calcium ions and aligning them in an orientation that matches the crystal structure of HA (7). Studies have shown that a peptide motif could promote the nucleation and growth of HA crystals (8 -10).…”

mentioning

confidence: 99%

C-terminal Amidation of an Osteocalcin-derived Peptide Promotes Hydroxyapatite Crystallization

Hosseini

Naderi-Manesh

Mountassif

et al. 2013

Journal of Biological Chemistry

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Background: A natural motif sequence was used as substrate to template hydroxyapatite (HA) formation. Results: HA crystal formation is attributed to C-terminal amidation of a natural peptide derived from osteocalcin. Conclusion: The chemical structure of the peptide controls HA crystal formation and growth. Significance: HA-binding peptides are relevant for biomimetic bone synthesis, hard tissue regeneration, and improvement of osseointegration of biomedical implants.

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Binding of Bone Sialoprotein, Osteopontin and Synthetic Polypeptides to Hydroxyapatite

Cited by 123 publications

References 39 publications

Delineation of the Hydroxyapatite-nucleating Domains of Bone Sialoprotein

Delineation of the Hydroxyapatite-nucleating Domains of Bone Sialoprotein

MC3T3-E1 cell adhesion to hydroxyapatite with adsorbed bone sialoprotein, bone osteopontin, and bovine serum albumin

C-terminal Amidation of an Osteocalcin-derived Peptide Promotes Hydroxyapatite Crystallization

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