2adw
Crystal strucutre of Echinomycin-(ACGTACGT)2 solved by SAD
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OverviewOverview
A new crystal form was obtained for the complex between (ACGTACGT)2 and, echinomycin and X-ray data were collected to 1.6 A. The structure was, phased by the SAD method based on a single unexpected anomalous scatterer, that could be identified as a mixture of nickel and zinc by measurements, of the anomalous scattering at different wavelengths. This cation is, coordinated by two guanines from two different duplexes and four water, molecules. The structure resembles previously reported crystal structures, of DNA-echinomycin complexes, except that three of the eight base pairs, flanking the echinomycin bisintercalator sites have the Watson-Crick, rather than the Hoogsteen configuration. Hoogsteen binding was found for, the corresponding base pairs of the crystallographically independent, duplex, indicating that the two configurations are very close in energy.
About this StructureAbout this Structure
2ADW is a Protein complex structure of sequences from [1] with , , , and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Serendipitous SAD phasing of an echinomycin-(ACGTACGT)2 bisintercalation complex., Cuesta-Seijo JA, Weiss MS, Sheldrick GM, Acta Crystallogr D Biol Crystallogr. 2006 Apr;62(Pt 4):417-24. Epub 2006, Mar 18. PMID:16552143
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