MUNIN: A new approach to multi-dimensional NMR spectra interpretation

A new method, MUNIN (Multi-dimensional NMR spectra interpretation), is intr oduced for the automated interpretation of three-dimensional NMR spectra. I t is based on a mathematical concept referred to as three-way decomposition . An NMR spectrum is decomposed into a sum of components, with each compone nt corresponding to one or a group of peaks. Each component is defined as t he direct product of three one-dimensional shapes. A consequence is reducti on in dimensionality of the spectral data used in further analysis. The dec omposition may be applied to frequency-domain or time-domain data, or to a mixture of these. Features of MUNIN include good resolution in crowded regi ons and the absence of assumptions about line shapes. Uniform sampling of t ime-domain data, a prerequisite for discrete Fourier transform, is not requ ired. This opens an avenue for the processing of NMR data that do not follo w oscillating behaviour, e.g. from relaxation measurements. The application of MUNIN is illustrated for a H-1-N-15-NOESY-HSQC, where each component is defined as the set of all NOE peaks formed by a given amide group. As a re sult, the extraction of structural information simply consists of one-dimen sional peak picking of the shape along the NOE-axis obtained for each amide group.