 Inter-proton distances can be determined from unambiguously assigned, well-resolved, high signal-to-noise NOESY spectra by analysis of cross peak intensities.These may be obtained by volume integration and can be converted into estimates of interproton distances.The distance between two atoms formula_42 and formula_43 can be calculated from the cross-peak volumes formula_44 and a scaling constant formula_45

where formula_45 can be determined based on measurements of known fixed distances.