MARDIGRAS - A PROCEDURE FOR MATRIX ANALYSIS OF RELAXATION FOR DISCERNING GEOMETRY OF AN AQUEOUS STRUCTURE

An accurate method for estimating distances from the two-dimensional nuclear Overhauser effect spectrum is described. The method entails a back-calculation of the relaxation matrix from the measured 2D NOE intensity matrix. While a straightforward back-calculation of distances will fail in the absence of all cross- and diagonal-peak intensities, the MARDIGRAS procedure supplements the observed intensities with calculated values from an arbitrary model and is less prone to the mathematical singularities encountered with an incomplete data set. Several model structures were used for generating the initial matrix of intensities for embedding the observed intensities, and the method is found to be relatively insensitive to the model structure. © 1990.