title: Direct methods and protein crystallography at low resolution.
abstract: The tools of modern direct methods are examined and their limitations for solving protein structures discussed. Direct methods need atomic resolution data (1.1-1.2 A) for structures of around 1000 atoms if no heavy atom is present. For low-resolution data, alternative approaches are necessary and these include maximum entropy, symbolic addition, Sayre's equation, group scattering factors and electron microscopy.
authors.affiliation: Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, Scotland. chris@chem.gla.ac.uk
authors.forename: C J
authors.initials: CJ
authors.lastname: Gilmore
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D018360:Crystallography, X-Ray / Q000379:methods*; D008962:Models, Theoretical; D018272:Porins / Q000737:chemistry; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; C109237:OmpF protein; D018272:Porins; D011506:Proteins