RT Journal Article
SR Electronic
T1 Measurement of Atom Resolvability in CryoEM Maps with Q-scores
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 722991
DO 10.1101/722991
A1 Pintilie, Grigore
A1 Zhang, Kaiming
A1 Su, Zhaoming
A1 Li, Shanshan
A1 Schmid, Michael F.
A1 Chiu, Wah
YR 2019
UL http://biorxiv.org/content/early/2019/08/05/722991.abstract
AB CryoEM density maps are now at the point where resolvability of individual atoms can be achieved. However, resolvability is not necessarily uniform throughout the map. We introduce a quantitative parameter to characterize the resolvability of individual atoms in cryoEM maps, the map Q-score. Q-scores can be calculated for atoms in proteins, nucleic acids, water, ligands, and other solvent atoms, using models fitted to or derived from cryoEM maps. Q-scores can also be averaged to represent larger features such as entire residues and nucleotides. Averaged over entire models, Q-scores correlate very well with the estimated resolution of cryoEM maps for both protein and RNA. Assuming the models they are calculated from are well-fitted to the map, Q-scores can thus be used as another measure to indicate resolvability of features in cryoEM maps at various scales, from entire complexes down to individual atoms. Q-score analysis of multiple cryoEM maps of the same proteins derived from different labs confirms reproducibility of structural features down to water and ion atoms.