Multiple simultaneous distance determinations:: Application of rotational echo double resonance nuclear magnetic resonance to IS2 spin networks

Rotational Echo DOuble Resonance (REDOR) NMR is an oft-demonstrated tool for measuring distance between isolated IS spin pairs. Its application to more complex ISn spin networks (n > 1), however, is rare, as in these systems the interpretation of the results is model-dependent-while it is precisely the measurement of multiple distances which is required for molecular structure elucidation. Recently, Theta-REDOR was introduced and was shown to improve interpretability at the cost of signal intensity. In this paper we analyze generalizations to the REDOR pulse sequence, and present a new experimental procedure which allows for simultaneous distance determinations in larger spin systems with improved signal intensity. Experimental data are presented for the IS2 spin system glycine-C-13(2)-N-15. (C) 2000 American Institute of Physics. [S0021-9606(00)00727-3].