The tripeptide RGD is well known for its role in integrin receptor-mediated cell-cell surface adhesion. Here, NMR and transferred NOE studies have been done with the fibrinogen/fibronectin-derived hexapeptide GRGDSP in the presence of sodium dodecyl sulfate (SDS) and purified platelet glycoprotein integrin receptor GPIIb/IIIa. In the presence of SDS and absence of receptor, GRGDSP gives NOE-based distance geometry-generated structures characteristic of two 'nested' β-turns centered at RG and GD. In the presence of integrin GPIIb/IIIa, GRGDSP resonances are chemically shifted and broadened consistent with a dynamic equilibrium between free and receptor 'bound' peptide. NOEs characteristic of the nested β-turns are either absent or weaker indicating a significant conformational change in GRGDSP in the receptor bound state. GRGDSP appears to bind the receptor in a more extended backbone conformation which positions aspartic acid and arginine residues spatially close for potential electrostatic interactions.
|Original language||English (US)|
|Number of pages||8|
|Journal||Biochimica et Biophysica Acta - Protein Structure and Molecular Enzymology|
|State||Published - Aug 15 1996|