title: Accurate protein crystallography at ultra-high resolution: valence electron distribution in crambin.
abstract: The charge density distribution of a protein has been refined experimentally. Diffraction data for a crambin crystal were measured to ultra-high resolution (0.54 A) at low temperature by using short-wavelength synchrotron radiation. The crystal structure was refined with a model for charged, nonspherical, multipolar atoms to accurately describe the molecular electron density distribution. The refined parameters agree within 25% with our transferable electron density library derived from accurate single crystal diffraction analyses of several amino acids and small peptides. The resulting electron density maps of redistributed valence electrons (deformation maps) compare quantitatively well with a high-level quantum mechanical calculation performed on a monopeptide. This study provides validation for experimentally derived parameters and a window into charge density analysis of biological macromolecules.
authors.affiliation: Laboratoire de Cristallographie et Modélisation des Matériaux Minéraux et Biologiques, Université Henri Poincaré-Nancy 1-Centre National de la Recherche Scientifique ESA 7036, BP 239, 54506 Vandoeuvre-lès-Nancy, France.
authors.forename: C
authors.initials: C
authors.lastname: Jelsch
authors.forename: M M
authors.initials: MM
authors.lastname: Teeter
authors.forename: V
authors.initials: V
authors.lastname: Lamzin
authors.forename: V
authors.initials: V
authors.lastname: Pichon-Pesme
authors.forename: R H
authors.initials: RH
authors.lastname: Blessing
authors.forename: C
authors.initials: C
authors.lastname: Lecomte
mesh_terms: D018360:Crystallography, X-Ray; D004583:Electrons; D010940:Plant Proteins / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D010940:Plant Proteins; C024934:crambin protein, Crambe abyssinica