title: lDDT: a local superposition-free score for comparing protein structures and models using distance difference tests.
abstract: BACKGROUND
  The assessment of protein structure prediction techniques requires objective criteria to measure the similarity between a computational model and the experimentally determined reference structure. Conventional similarity measures based on a global superposition of carbon α atoms are strongly influenced by domain motions and do not assess the accuracy of local atomic details in the model.
  
  
  RESULTS
  The Local Distance Difference Test (lDDT) is a superposition-free score that evaluates local distance differences of all atoms in a model, including validation of stereochemical plausibility. The reference can be a single structure, or an ensemble of equivalent structures. We demonstrate that lDDT is well suited to assess local model quality, even in the presence of domain movements, while maintaining good correlation with global measures. These properties make lDDT a robust tool for the automated assessment of structure prediction servers without manual intervention.
  
  
  METHODS
  Source code, binaries for Linux and MacOSX, and an interactive web server are available at http://swissmodel.expasy.org/lddt.
  
  
  BACKGROUND
  torsten.schwede@unibas.ch.
  
  
  BACKGROUND
  Supplementary data are available at Bioinformatics online.
authors.affiliation: Biozentrum, Universität Basel, Klingelbergstrasse 50-70 and Computational Structural Biology, SIB Swiss Institute of Bioinformatics, 4056 Basel, Switzerland.
authors.forename: Valerio
authors.initials: V
authors.lastname: Mariani
authors.forename: Marco
authors.initials: M
authors.lastname: Biasini
authors.forename: Alessandro
authors.initials: A
authors.lastname: Barbato
authors.forename: Torsten
authors.initials: T
authors.lastname: Schwede
mesh_terms: D019295:Computational Biology / Q000379:methods; D008958:Models, Molecular; D011487:Protein Conformation; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry; D012984:Software; D013237:Stereoisomerism
chemical_list: D011506:Proteins