1vro
From Proteopedia
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Selenium-Assisted Nucleic Acid Crystallography: Use of Phosphoroselenoates for MAD Phasing of a DNA Structure
Overview
The combination of synchrotron radiation and a variety of atoms or ions, (either covalently attached to the biomolecule prior to crystallization or, soaked into crystals) that serve as anomalous scatterers constitutes a, powerful tool in the X-ray crystallographer's repertoire of structure, determination techniques. Phosphoroselenoates in which one of the, nonbridging phosphate oxygens in the backbone is replaced by selenium, offer a simplified means for introducing an anomalous scatterer into, oligonucleotides by conventional solid-phase synthesis. Unlike other, methods that are used to derivatize DNA or RNA by covalent attachment of a, heavy atom (i.e., bromine at the C5 position of pyrimidines), tedious, synthesis of specialized nucleosides is not required. Introduction of, selenium is readily accomplished in solid-phase oligonucleotide synthesis, by replacing the standard oxidation agent with a solution of potassium, selenocyanide. This results in a diastereomeric mixture of, phosphoroselenoates that can be separated by strong anion-exchange HPLC., As a test case, all 10 DNA hexamers of the sequence CGCGCG containing a, single phosphoroselenoate linkage (PSe) were prepared. Crystals were grown, for a subset of them, and the structure of [d(C(PSe)GCGCG)](2) was, determined by the multiwavelength anomalous dispersion technique and, refined to 1.1 A resolution.
About this Structure
1VRO is a Protein complex structure of sequences from [1] with SPM and MG as ligands. This structure superseeds the now removed PDB entry 1N6S. Full crystallographic information is available from OCA.
Reference
Selenium-assisted nucleic acid crystallography: use of phosphoroselenoates for MAD phasing of a DNA structure., Wilds CJ, Pattanayek R, Pan C, Wawrzak Z, Egli M, J Am Chem Soc. 2002 Dec 18;124(50):14910-6. PMID:12475332
Page seeded by OCA on Sat Nov 24 23:06:51 2007
