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Volume 20, Issue 4, Pages 153-167

Single scan TROSY and E.COSY suite of experiments for the measurement of residual dipolar couplings in proteins

Tommaso Eliseo,1 Mariana Gallo,1 Riccardo Melis,1 Maurizio Paci,1 Renzo Bazzo,2 and Daniel O. Cicero1

1Department of Chemical Science and Technology, University of Rome “Tor Vergata”, via della Ricerca Scientifica 1, 00133 Rome, Italy
2IRBM “P. Angeletti”, Via Pontina km 30.600, 00040, Pomezia, Rome, Italy

Copyright © 2006 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Simple modifications of the gradient enhanced version of the TROSY experiment allow to obtain four different spectra containing each one of the components of the H–N doublet in 15N labelled proteins. By measuring the difference in peak position among these four spectra, residual dipolar coupling values can be obtained for medium sized proteins. This experiment, which exploits the use of pulse field gradients to select the 15N coherence pathway, produces excellent results in terms of water suppression. Moreover, tuning of a single delay in the sequence reduces notably the presence of artifacts. The performance of this suite of experiments, that we called TEC (Trosy–E.Cosy) experiment, is tested against a J-modulation method, inherently more accurate but more time consuming, for the accuracy in the observed values of residual dipolar couplings. For larger proteins, the use of this strategy allows to select the most favourable combination of peaks giving the sharpest signals.