title: Objectively judging the quality of a protein structure from a Ramachandran plot.
abstract: BACKGROUND
  Statistical methods that compare observed and expected distributions of experimental observables provide powerful tools for the quality control of protein structures. The distribution of backbone dihedral angles ('Ramachandran plot') has often been used for such quality control, but without a firm statistical foundation.
  
  
  RESULTS
  A new and-simple method is presented for judging the quality of a protein structure based on the distribution of backbone dihedral angles. Inputs to the method are 60 torsion angle distributions extracted from protein structures solved at high resolution; one for each combination of residue type and tri-state secondary structure. Output for a protein is a Ramachandran Z-score, expressing the quality of the Ramachandran plot relative to current state-of-the-art structures.
authors.affiliation: EMBL, Heidelberg, Germany. r.hooft@euromail.com
authors.forename: R W
authors.initials: RW
authors.lastname: Hooft
authors.forename: C
authors.initials: C
authors.lastname: Sander
authors.forename: G
authors.initials: G
authors.lastname: Vriend
mesh_terms: D000465:Algorithms; D001699:Biometry; D016208:Databases, Factual; D005069:Evaluation Studies as Topic; D015394:Molecular Structure; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry*; D012984:Software
chemical_list: D011506:Proteins