title: A magic triangle for experimental phasing of macromolecules.
abstract: Obtaining phase information for the solution of macromolecular structures is still one of the bottlenecks in X-ray crystallography. 5-Amino-2,4,6-triiodoisophthalic acid (I3C), in which three covalently bound iodines form an equilateral triangle, was incorporated into proteins in order to obtain phases by single-wavelength anomalous dispersion (SAD). An improved binding capability compared with simple heavy-metal ions, ready availability, improved recognition of potential heavy-atom sites and low toxicity make I3C particularly suitable for experimental phasing.
authors.affiliation: Department of Structural Chemistry, Georg-August-Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany. tbeck@shelx.uni-ac.gwdg.de
authors.forename: Tobias
authors.initials: T
authors.lastname: Beck
authors.forename: Andrius
authors.initials: A
authors.lastname: Krasauskas
authors.forename: Tim
authors.initials: T
authors.lastname: Gruene
authors.forename: George M
authors.initials: GM
authors.lastname: Sheldrick
mesh_terms: D000818:Animals; D001665:Binding Sites; D002645:Chickens; D003460:Crystallization; D018360:Crystallography, X-Ray / Q000379:methods; D006860:Hydrogen Bonding; D046911:Macromolecular Substances / Q000737:chemistry* / Q000378:metabolism; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D010196:Pancreatic Elastase / Q000737:chemistry* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D013552:Swine; D014283:Triiodobenzoic Acids / Q000378:metabolism*
chemical_list: D046911:Macromolecular Substances; D010940:Plant Proteins; D014283:Triiodobenzoic Acids; C003427:thaumatin protein, plant; C480700:5-amino-2,4,6-triiodoisophthalic acid; C421864:hen egg lysozyme; D009113:Muramidase; D010196:Pancreatic Elastase