Abstact

The solution structure of the C-terminal SH2 domain of phospholipase C-gamma 1 (PLC-gamma 1), in complex with a phosphopeptide corresponding to its Tyr-1021 high affinity binding site on the platelet-derived growth factor receptor, has been determined by nuclear magnetic resonance spectroscopy. The topology of the SH2-phosphopeptide complex is similar to previously reported Src and Lck SH2 complexes. However, the binding site for residues C-terminal to the phosphotyrosine (pTyr) is an extended groove that contacts peptide residues at the +1 to +6 positions relative to the pTyr. This striking difference from Src and Lck reflects the fact that the PLC-gamma 1 complex involves binding of a phosphopeptide with predominantly hydrophobic residues C-terminal to the pTyr and therefore serves as a prototype for a second class of SH2-phosphopeptide interactions.