MUSIC and aromatic residues:: Amino acid type-selective 1H-15N correlations, III

Amino acid type-selective experiments can help to remove ambiguities in automated assignment procedures for N-15/C-13-labeled proteins. Here we present five triple-resonance experiments that yield amino acid type-selective H-1-N-15 correlations for aromatic amino acids. Four of the novel experiments are based on the MUSIC coherence transfer scheme that replaces the initial INEPT transfer and is selective for CH2. The MUSIC sequence is combined with selective excitation pulses to create experiments for Trp (W-HSQC) as well as Phe, Tyr, and His (FYH-HSQC). In addition, an experiment selective for Trp H-epsilon1-N-epsilon1 is presented. The new experiments are recorded as two-dimensional experiments and their performance is demonstrated with the application to a protein domain of 115 amino acids. (C) 2001 Elsevier Science.