| Autor: |
Wuttke, Martina, Müller, Stefan, Nitsche, D. Patric, Paulsson, Mats, Hanisch, Franz-Georg, Maurer, Patrik |
| Zdroj: |
Journal of Biological Chemistry; September 2001, Vol. 276 Issue: 39 p36839-36848, 10p |
| Abstrakt: |
Human bone sialoprotein (BSP) comprises 15% of the total noncollagenous proteins in bone and is thought to be involved in bone mineralization and remodeling. Recent data suggest a role for BSP in breast cancer and the development of bone metastases. We have produced full-length recombinant BSP in a human cell line and purified the protein from human bone retaining the native structure with proper folding and post-translational modifications. Mass spectrometry of bone-derived BSP revealed an average mass of 49 kDa and for recombinant BSP 57 kDa. The post-translational modifications contribute 30–40%. Carbohydrate analysis revealed 10 different complex-typeN-glycans on both proteins and eight differentO-glycans on recombinant BSP, four of those were found on bone-derived BSP. We could identify eight threonines modified byO-glycans, leaving the C terminus of the protein free of glycans. The recombinant protein showed similar secondary structures as bone-derived BSP. BSP was visualized in electron microscopy as a globule linked to a thread-like structure. The affinity for hydroxyapatite was higher for bone-derived BSP than for recombinant BSP. Cell adhesion assays showed that the binding of BSP to cells can be reversibly diminished by denaturation. |
| Databáze: |
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