A new assignment technique of 2D‐NMR spectra by spin‐lock sequence to a tripeptide containing tryptophan in water

We developed a new assignment technique of tryptophan residues using pulsed field gradient TOCSY–ROESY (PFG‐TORO) and pulsed field gradient TOCSY–ROESY–TOCSY (PFG‐TOROTO) techniques in water. Connectivity from βH to ζ2H (H‐7) via ε1H (H‐1) and δ1H (H‐2) in the TORO spectrum and from βH to ζ3H (H‐5) and η2H (H‐6) via ε1H (H‐1) and δ1H (H‐2) in the TOROTO spectrum could be able to assign each of the protons of the indole rings. Copyright © 2010 John Wiley & Sons, Ltd.