title: Ultrahigh-resolution crystallography and related electron density and electrostatic properties in proteins.
abstract: With an increasing number of biological macromolecular crystal structures measured at ultrahigh resolution (1 A or better), it is necessary to extend to large systems the experimental valence electron density modelling that is applied to small molecules. A database of average multipole populations has been built, describing the electron density of chemical groups in all 20 amino acids found in proteins. It allows calculation of atomic aspherical scattering factors, which are the starting point for refinement of the protein electron density, using the MoPro software. It is shown that the use of non-spherical scattering factors has a major impact on crystallographic statistics and results in a more accurate crystal structure, notably in terms of thermal displacement parameters and bond distances involving H atoms. It is also possible to obtain a realistic valence electron density model, which is used in the calculation of the electrostatic potential and energetic properties of proteins.
authors.affiliation: Laboratoire de Cristallographie et de Modélisation des Matériaux Minéraux et Biologiques (LCM3B), CNRS ESA 7036, UHP Faculté des Sciences, BP 239, 54506 Vandoeuvre-les-Nancy CEDEX, France. claude.lecomte@lcm3.uhp-nancy.fr
authors.forename: Claude
authors.initials: C
authors.lastname: Lecomte
authors.forename: Christian
authors.initials: C
authors.lastname: Jelsch
authors.forename: Benoît
authors.initials: B
authors.lastname: Guillot
authors.forename: Bertrand
authors.initials: B
authors.lastname: Fournier
authors.forename: Angélique
authors.initials: A
authors.lastname: Lagoutte
mesh_terms: D003461:Crystallography / Q000379:methods*; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D011506:Proteins