Table 2.

Web accessible servers providing Knowledge-Based (KB) and/or Model vs Data (MvD) protein NMR structure quality assessment reports.

Server	url	Validation statistics provided
CING [62]v.1.0: Common Interface for NMR Structure Generation	http://nmr.cmbi.ru.nl/cing/Home.html	KB: Bond lengths and bond angles, backbone Ramachandran distributions, peptide omegas, packing, sidechain rotomer normalilty, disulfides, salt-bridges, chemical shift validations. Provides residue-specific ROC scores [69]. Uses DSSP [70,71], WHATIF [72], PROCHECK [15,73], and BMRB chemical shift validation.
		MvD: DOAP analysis. Restraint violation analysis, redundancy and duplicated restraints, back calculation of chemical shift from structure. Uses SHIFTX [49] and VASCO [74].
Molprobity [11]	http://molprobity.biochem.duke.edu/	KB: Backbone Ramachandran distributions, peptide omegas, packing, H-bond satisfaction, sidechain rotomer normalilty.
		MvD: RDC analysis with RDCvis[75].
PSVS [10,14] v.1.5. Protein Structure Validation Software suite.	http://psvs.nesg.org/	KB: Bond lengths and bond angles, backbone Ramachandran distributions, peptide omegas, packing, sidechain rotomer normality, chemical shift validation and completeness using AVS [68]. Provides Z scores relative to high-resolution crystal strutures for ProsaII [12], Verify3D [13], Procheck_bb [15,73], Procheck_all [15,73], and MolProbity [11]. Also uses DSSP [70,71], PDBStat [20], , LACS [76], and PDB Clash score (deposit.rcsb.org/validate).
		MvD: DAOP or Variance Matrix analysis. Restraint violation analysis, redundancy and duplicated restraints, NOE completeness, NOE DP scores, RDC Q scores, and GLM-RMSD [31] “equivalent resolution” score. Provides mapping of Ramachanran outliers and RPF violations onto 3D structure. Also uses PDBStat [20], FindCore [20,58,59], and RPF [29,30] software.
ResProx [43] Resolution by Proxy	http://www.resprox.ca/	KB: Assesses “equivalent resolution” based on 25 protein features including backbone Ramachandran distributions, peptide omegas, H-bond geometry, over and underpacking. Uses Vader [40], PROSESS [42], Molprobity [11], RosettaHoles [17], and GeNMR [41] software.
		KB: Bond lengths and bond angles, peptide omegas, chemical shift validations, backbone Ramachandran distributions, CING [62] ROC scores. Uses WHATIF [72], CING [62], and VASCO [74].
Vivaldi [64] v.1: Visualization and validation of biomacromolecular NMR structures from the PDB	http://www.ebi.ac.uk/pdbe/vivaldi/	MvD: DAOP and Variance Matrix analysis. Restraint violation and RDC analysis. Uses NMRCore [77]