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11. Equivalent resolution


The Equivalent resolution plots are intended as a very approximate guide to how the geometry of the models in the NMR ensemble compare with that of X-ray crystal structures solved at different resolutions.

The 5 properties plotted are:-

  1. Ramachandran plot quality assessment - giving the percentage of residues in the "core" region of the Ramachandran plot.
  2. Main-chain hydrogen bond energies - giving the standard deviation of the hydrogen bond energies for main-chain hydrogen bonds. The energies are calculated using the method of Kabsch & Sander (1983).
  3. Chi-1 pooled standard deviations - giving the standard diviations of the chi-1 values from their nearest favoured conformation (ie gauche minus, trans and chi1 gauche).
  4. Standard deviation of Chi-2 trans angle - giving the standard deviation of only the trans chi-2 dihedral angles.
  5. Overall G-factor - giving a measure of the overall `normality' of the structure from an average of all the different G-factors for each residue in the structure.

The first 4 of these properties were found to correlate with resolution by Morris et al. (1992). The fifth also shows a good correlation (Laskowski R A, unpublished results).


The main options for the Equivalent resolution are:-

These options can be altered by editing the parameter file, procheck_nmr.prm, as described here.

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