This section describes how to back-calculate NOESY spectra from a three-dimensional structure of a molecule, and how to refine an initial model by directly minimizing the difference between the observed 2D NOE intensities and those calculated by the full relaxation matrix approach. Spin diffusion effects are thus accounted for fully during the refinement. Derivatives with respect to atomic coordinates are calculated analytically (Yip and Case 1989). An example of a refinement with this method is Nilges et al. (1991).
For further reading, see Ernst, Bodenhausen, and Wokaun (1987), James et al. (1991), Keepers and James (1984), Lipari and Szabo (1982), Macura and Ernst (1980), Nilges et al. (1991), Solomon (1955), and Yip and Case (1989).