Robust and versatile interpretation of spectra with coupled evolution periods using multi-way decomposition.

Coupling of evolution periods in NMR experiments is a very promising approach that has recently attracted much attention for its substantial savings in measurement time. Another novel concept, which has already proved useful in many types of NMR applications is multi-way decomposition. The PRODECOMP tool described here addresses the combination of these two modern tools in protein NMR. The following properties of this approach are described and illustrated. Highly similar information to what would be found in a corresponding full-dimensional spectrum is extracted from a set of projected spectra. All experimental spectra are used simultaneously, avoiding sensitivity loss associated with individual examination of the spectra. Aliasing caused by the linear combinations of individual shifts in the projected spectra is automatically resolved, allowing for better resolution due to smaller spectral widths. Reconstructions of various high-dimensional spectra, including the corresponding full-dimensional spectrum become straightforward. Spectral overlap is efficiently resolved. The capabilities of PRODECOMP are illustrated for a 14 kD protein, for which 12 projections of a 5-dimensional spectrum with the nuclei N, HN, CO, Calpha and Halpha are analysed.