Amino acid type-selective backbone H-1-N-15-correlations for Arg and Lys

Four novel amino acid type-selective triple resonance experiments to identi fy the backbone amino proton and nitrogen resonances of Arg and Lys and of their sequential neighbors in (C-13,N-15)-labeled proteins are presented: t he R(i+1)-HSQC and R(i,i+1)-HSQC select signals originating from Arg side c hains, the K(i+1)-HSQC and K(i,i+1)-HSQC select signals originating from Ly s side chains. The selection is based on exploiting the characteristic chem ical shifts of a pair of carbon atoms in Arg and Lys side chains using sele ctive 90 degrees pulses. The new experiments are recorded as two-dimensiona l H-1-N-15-correlations and their performance is demonstrated with the appl ication to a protein domain of 83 amino acids.