An α/β-HSQC-α/β Experiment for Spin-State Selective Editing of IS Cross Peaks

A generalized version of the TROSY experiment allows the spin-state selective editing of the four multiplet components of ¹⁵ N- ¹ H cross peaks of amide groups in proteins into four different subspectra, with no penalty in sensitivity. An improvement by √2 in sensitivity results, if only two of the four multiplet components are selected. Use of the experiment for the measurement of ¹ J _HN coupling constants is discussed. A water flip-back version of the experiment is demonstrated with a 45 kDa fragment of ¹⁵ N/ ² H labeled Staphylococcus aureus gyrase B.