Synthesis and function of an O-phosphorylated peptide corresponding to the cell adhesion sequence of bone sialoprotein (BSP).
Bone sialoprotein contains a cell-binding RGD sequence followed by a threonine residue. Since the protein is extensively phosphorylated, this threonine may also be modified. To study whether such a phosphorylation may alter cell-binding properties, the hexapeptide Pro-Arg-Gly-Asp-Thr(O-phosphoryl)-Tyr has been synthesized by the Fmoc technique using benzyl protective groups for Tyr and phosphate, tert-butyl ester for Asp and Pmc for Arg. Removal of Fmoc groups was effected by treatment with 20% morpholine in DMF. The phospho-peptide inhibited binding of R1 cells to BSP-coated surfaces 10 times less efficiently compared with the non-phosphorylated peptide, as did, surprisingly, also the fibronectin-derived peptide Gly-Arg-Gly-Asp-Ser-Pro.
Larsson
E
E
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Sweden.
Lüning
B
B
Heinegård
D
D
D000595:Amino Acid Sequence; D000818:Animals; D002448:Cell Adhesion; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism; D007202:Indicators and Reagents; D058574:Integrin-Binding Sialoprotein; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010766:Phosphorylation; D051381:Rats; D012795:Sialoglycoproteins / Q000138:chemical synthesis* / Q000378:metabolism; D016339:Spectrometry, Mass, Fast Atom Bombardment
D007202:Indicators and Reagents; D058574:Integrin-Binding Sialoprotein; D012795:Sialoglycoproteins