title: Sheldrick's 1.2 A rule and beyond.
abstract: An average profile of squared normalized structure factors as a function of resolution, /E/2>(d*), calculated from a large ensemble of high-resolution protein models, is presented. An interpretation is given that provides a structural explanation for Sheldrick's 1.2 A rule for the applicability of direct methods. The implications for the potential effectiveness of extended direct methods, incorporating stereochemical knowledge, are discussed.
authors.affiliation: Global Phasing Ltd, Sheraton House, Castle Park, Cambridge CB3 0AX, England.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Morris
authors.forename: Gérard
authors.initials: G
authors.lastname: Bricogne
mesh_terms: D000465:Algorithms; D018360:Crystallography, X-Ray; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*
chemical_list: D011506:Proteins