Offset profiles of selective pulses in isotopically labeled macromolecules

The experimental verification of offset profiles and calibration of selecti ve pulses in NMR is usually carried out with doped water samples but not un der conditions typical of macromolecules with short T-2, long T-1, and poss ibly homo- and heteronuclear couplings. A new method for selective excitati on in isotopically labeled macromolecules is shown to be particularly suite d to this purpose. This is illustrated for a backbone amide resonance in a sample of N-15-labeled human ubiquitin, (C) 1999 Academic Press.