title: Interaction of an echinomycin-DNA complex with manganese ions.
abstract: The crystal structure of an echinomycin-d(ACGTACGT) duplex interacting with manganese(II) was solved by Mn-SAD using in-house data and refined to 1.1 A resolution against synchrotron data. This complex crystallizes in a different space group compared with related complexes and shows a different mode of base pairing next to the bis-intercalation site, suggesting that the energy difference between Hoogsteen and Watson-Crick pairing is rather small. The binding of manganese to N7 of guanine is only possible because of DNA unwinding induced by the echinomycin, which might help to explain the mode of action of the drug.
authors: Department of Structural Chemistry, University of Göttingen, 37077 Göttingen, Germany.
authors: Roland
authors: R
authors: Pfoh
authors: Jose A
authors: JA
authors: Cuesta-Seijo
authors: George M
authors: GM
authors: Sheldrick
mesh_terms: D020029:Base Pairing; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D004448:Echinomycin / Q000737:chemistry*; D007477:Ions; D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular
chemical_list: D007477:Ions; D008345:Manganese; D004448:Echinomycin; D004247:DNA