title: Extending molecular-replacement solutions with SHELXE.
abstract: Although the program SHELXE was originally intended for the experimental phasing of macromolecules, it can also prove useful for expanding a small protein fragment to an almost complete polyalanine trace of the structure, given a favourable combination of native data resolution (better than about 2.1 Å) and solvent content. A correlation coefficient (CC) of more than 25% between the native structure factors and those calculated from the polyalanine trace appears to be a reliable indicator of success and has already been exploited in a number of pipelines. Here, a more detailed account of this usage of SHELXE for molecular-replacement solutions is given.
authors.affiliation: Department of Haematology, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, England.
authors.forename: Andrea
authors.initials: A
authors.lastname: Thorn
authors.forename: George M
authors.initials: GM
authors.lastname: Sheldrick
mesh_terms: D000465:Algorithms; D019943:Amino Acid Substitution; D015415:Biomarkers / Q000737:chemistry; D003208:Concanavalin A / Q000737:chemistry; D018360:Crystallography, X-Ray / Q000379:methods; D046911:Macromolecular Substances / Q000737:chemistry; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D017434:Protein Structure, Tertiary; D015203:Reproducibility of Results; D053838:Scattering, Small Angle; D012984:Software; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D015415:Biomarkers; D046911:Macromolecular Substances; D010446:Peptide Fragments; D010455:Peptides; D003208:Concanavalin A; C019529:polyalanine
keywords: SHELX; autotracing; density modification; molecular replacement