Figure 1

Distribution of disulfide strain energies in NMR and X-ray structures. A. Number of disulfide bonds for each dihedral strain energy (in 2.5 kJ.mol^-1 increments) for structures determined by NMR (total of 55,005 disulfides, Table 2) and X-ray (total of 42,690 disulfides, Table 1). B. Plot of the mean strain energy and 95% confidence intervals of each disulfide configuration versus the incidence of that configuration. The dotted lines are the linear least-squares fit to the NMR data (top line; Table 2) or single exponential least squares fit to the X-ray data (bottom line; Table 1). C. Plot of the mean strain energy and 95% confidence intervals of each disulfide configuration versus the incidence of that configuration for all X-ray disulfides (42,690 disulfides; see part B), a unique set of 6,874 X-ray disulfides described by Schmidt et al. [8] (data set 1) and the 16,225 disulfides of a culled set of X-ray structures described by Guoli Wang and Roland Dunbrack, Jr. [25] (data set 2).