Nuclear magnetic resonance and restrained molecular dynamics studies of the interaction of an epidermal growth factor-derived peptide with protein tyrosine phosphatase 1B

The epidermal growth factor-derived (EGFR988) fluorophosphonate peptide, DA DE(F(2)Pmp)-L, is a potent (30 pM) inhibitor of the protein tyrosine phosph atase PTP1B. Nuclear magnetic resonance (NMR) transferred nuclear Overhause r effect (nOe) experiments have been used to determine the conformation of DADE(F(2)Pmp)L while bound in the active site of PTP1B. When bound, the pep tide adopts an extended beta-strand conformation. Molecular modeling and mo lecular dynamics simulations allowed the elucidation of the sources of many of the interactions leading to binding of this inhibitor. Electrostatic, h ydrophobic, and hydrogen-bonding interactions were all found to contribute significantly to its binding. However, despite the overall tight binding of this inhibitor, the N-terminal and adjacent residue of the peptide were vi rtually unrestrained in their motion. The major contributions to binding ar ose from hydrophobic interactions at the leucine and at the aromatic center , hydrogen bonding to the pro-R fluorine of the fluorophosphonomethyl group , and electrostatic interactions involving the carboxylate functionalities of the aspartate and glutamate residues. These latter two residues were fou nd to form tight contacts with surface recognition elements (arginine and l ysine) situated near the active-site cleft.