Skip to main content
. 2021 Feb 4;18(2):156–164. doi: 10.1038/s41592-020-01051-w

Table 2.

Evaluated metrics

Metric class Package metric definition
Fit-to-Map
Correlation Coefficient, all voxels

Phenix CCbox full grid map versus model-map density correlation coefficient19

TEMPy CCC full grid map versus model-map density correlation coefficient17

Correlation Coefficient, selected voxels

Phenix CCmask map versus model-map density, only modeled regions19

Phenix CCpeaks map versus model-map density, only high-density map and model regions19

TEMPy CCC_OV map versus model-map density, overlapping map and model regions18

TEMPy SMOC Segment Manders’ Overlap, map versus model-map density, only modeled regions18

Correlation Coefficient, other density function

TEMPy LAP map versus model-map Laplacian filtered density (partial second derivative)16

TEMPy Mutual Information (MI) map versus model-map Mutual Information entropy-based function16

TEMPy MI_OV map versus model-map Mutual Information, only modeled regions18

Correlation Coefficient, atom positions Chimera/MAPQ Q-score map density at each modeled atom versus reference Gaussian density function8
FSC

Phenix FSC05 Resolution (distance) of Map-Model FSC curve read at point FSC = 0.5 (ref. 19)

CCPEM/Refmac FSCavg FSC curve area integrated to map resolution limit13,42

Atom Inclusion

EMDB/VisualAnalysis AI all Atom Inclusion, percentage of atoms inside depositor-provided density threshold14

TEMPy ENV Atom Inclusion in envelope corresponding to sample molecular weight; penalizes unmodeled regions16

Sidechain Density Phenix EMRinger evaluates backbone by sampling map density around Cɣ-atom ring paths for nonbranched residues15
Coordinates-only
Configuration

Phenix Bond r.m.s.d. of bond lengths21

Phenix Angle r.m.s.d. of bond angles21

Phenix Chiral r.m.s.d. of chiral centers21

Phenix Planar r.m.s.d. of planar group planarity21

Phenix Dihedral r.m.s.d. of dihedral angles21

Clashes MolProbity Clashscore Number of steric overlaps ≥0.4 Å per 1,000 atoms20
Conformation

MolProbity Rotamer sidechain conformation outliers20

MolProbity Rama Ramachandran ɸ,ψ main chain conformation outliers20

MolProbity CaBLAM outliers CO and Cɑ-based virtual dihedrals22

MolProbity Calpha outliers Cɑ-based virtual dihedrals and Cɑ virtual bond angle22

Versus Reference Model
Atom Superposition

Local Global Alignment (LGA) GDT-TS Global Distance Test Total Score, average percentage of model Cɑ that superimpose with reference Cɑ, multiple distance cutoffs23

LGA GDC Global Distance Calculation, average percentage of all model atoms that superimpose with reference, multiple distance cutoffs23

LGA GDC-SC Global Distance Calculation for sidechain atoms only23

OpenStructure/QS CaRMSD r.m.s.d. of Cɑ atoms25

Interatomic Distances LDDT LDDT Local Difference Distance Test, superposition-free comparison of all-atom distance maps between model and reference24
Contact Area

CAD CAD Contact Area Difference, superposition-free measure of differences in interatom contacts26

HBPLUS50 HBPR>6, hydrogen bond precision, nonlocal. fraction of correctly placed hydrogen bonds in residue pairs with >6 separation in sequence

Comparison among models
Atom Superposition, Multiple DAVIS-QA average of pairwise LGA GDT-TS scores among submitted models27