NMR PULSE SCHEMES FOR THE SEQUENCE-SPECIFIC ASSIGNMENT OF ARGININE GUANIDINO N-15 AND H-1 CHEMICAL-SHIFTS IN PROTEINS

A family of 2D NMR experiments is presented for the sequence-specific assignment of arginine guanidino H-1 and N-15 chemical shifts based on the transfer of magnetization exclusively by scalar connectivities. Because of the potential for significant exchange with water at the epsilon and eta positions along the side chain of arginine residues, care has been taken to minimize saturation and dephasing of water throughout the course of the pulse schemes. Attempts are made to minimize the effects of chemical exchange due to moderately slow rotation about the N-epsilon-C-zeta bond of arginine. The methods are demonstrated on a 1.5 mM sample of the C-terminal SH2 domain from phospholipase-C gamma 1 in complex with a 12-residue phosphotyrosyl peptide comprising its high-affinity binding site in the platelet-derived growth factor receptor.