Computer assisted assignment of C-13 or N-15 edited 3D-NOESY-HSQC spectra using back calculated and experimental spectra

A new tool, for the simulation of N-15 or C-13 edited 3D-NOESY-HSQC spectra using the complete relaxation matrix approach, has been developed and inte grated in the program AURELIA, This tool should be particularly useful for the fast and reliable computer assisted assignment of 3D-NOESY-HSQC spectra by comparing back-calculated and experimental spectra in an iterative proc ess. Folded spectra are sometimes used to enhance the digital resolution in the indirect dimensions of multidimensional spectra, However, these spectr a are usually difficult to analyze. To simplify this assignment process we have incorporated the simulation and automated annotation of folded peaks i nto the program. It is hereby possible to simulate multiple folding in all three dimensions of 3D N-15- Or C-13-NOESY-HSQC spectra, By comparing exper imental 3D-NOESY-HSQC spectra with spectra back calculated from a single tr ial structure or a set of trial structures, a user can easily check if the final structures explain all experimental NOEs, The new feature has been su ccessfully tested with the histidine-containing phosphocarrier protein HPr from Staphylococcus Carnosus. (C) 1999 Academic Press.