title: Metrics for comparison of crystallographic maps.
abstract: Numerical comparison of crystallographic contour maps is used extensively in structure solution and model refinement, analysis and validation. However, traditional metrics such as the map correlation coefficient (map CC, real-space CC or RSCC) sometimes contradict the results of visual assessment of the corresponding maps. This article explains such apparent contradictions and suggests new metrics and tools to compare crystallographic contour maps. The key to the new methods is rank scaling of the Fourier syntheses. The new metrics are complementary to the usual map CC and can be more helpful in map comparison, in particular when only some of their aspects, such as regions of high density, are of interest.
authors.affiliation: Centre for Integrative Biology, Department of Integrated Structural Biology, IGMBC, CNRS UMR 7104-INSERM U964-Université de Strasbourg, 1 Rue Laurent Fries, BP 10142, 67404 Illkirch, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Urzhumtsev
authors.affiliation: Lawrence Berkeley National Laboratory, One Cyclotron Road, BLDG 64R0121, Berkeley, CA 94720, USA.
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Afonine
authors.affiliation: Institute of Mathematical Problems of Biology, Russian Academy of Sciences, Pushchino 142290, Russian Federation.
authors.forename: Vladimir Y
authors.initials: VY
authors.lastname: Lunin
authors.affiliation: Los Alamos National Laboratory, Los Alamos, NM 87545-0001, USA.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Terwilliger
authors.affiliation: Lawrence Berkeley National Laboratory, One Cyclotron Road, BLDG 64R0121, Berkeley, CA 94720, USA.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Adams
mesh_terms: D018360:Crystallography, X-Ray / Q000379:methods*; D005583:Fourier Analysis; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry; D015203:Reproducibility of Results
chemical_list: D010455:Peptides
keywords: Fourier syntheses; correlation coefficients; crystallographic contour maps; map comparison; rank scaling; sigma scale