title: Improving multiple isomorphous replacement phasing by heavy-atom refinement using solvent-flattened phases.
abstract: Solvent flattening of macromolecular MIR electron density maps is frequently used to improve the quality of the phases and the interpretability of resultant electron density maps. A new method is presented by which the heavy-atom parameters of isomorphous derivatives are refined against these same solvent-flattened phases and is shown to enhance convergence of the parameters by decoupling heavy-atom-parameter adjustment from parent-phase calculation. This approach is described here in the first example of its application in the solution of the glutaminyl-tRNA synthetase-tRNA(Gln)-ATP co-crystal structure.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, CT 06511.
authors.forename: M A
authors.initials: MA
authors.lastname: Rould
authors.forename: J J
authors.initials: JJ
authors.lastname: Perona
authors.forename: T A
authors.initials: TA
authors.lastname: Steitz
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D005975:Glutamate-tRNA Ligase / Q000737:chemistry* / Q000378:metabolism; D012352:RNA, Transfer, Glu / Q000737:chemistry* / Q000378:metabolism; D012997:Solvents; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D012352:RNA, Transfer, Glu; D012997:Solvents; D000255:Adenosine Triphosphate; D005975:Glutamate-tRNA Ligase