2bq2

Solution Structure of the DNA Duplex ACGCGU-NA with a 2' Amido-Linked Nalidixic Acid Residue at the 3' Terminal Nucleotide

spinqualitylabelsall models 2bq2 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2bq2 is a 2 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR Ligands: 2AU, NIX Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Quinolones are antibacterial drugs that are thought to bind preferentially to disturbed regions of DNA. They do not fall into the classical categories of intercalators, groove binders or electrostatic binders to the backbone. We solved the 3D structure of the DNA duplex (ACGCGU-NA)2, where NA denotes a nalidixic acid residue covalently linked to the 2'-position of 2'-amino-2'-deoxyuridine, by NMR and restrained torsion angle molecular dynamics (MD). In the complex, the quinolones stack on G:C base pairs of the core tetramer and disrupt the terminal A:U base pair. The displaced dA residues can stack on the quinolones, while the uracil rings bind in the minor groove. The duplex-bridging interactions of the drugs and the contacts of the displaced nucleotides explain the high UV-melting temperature for d(ACGCGU-NA)2 of up to 53 degrees C. Further, non-covalently linked complexes between quinolones and DNA of the sequence ACGCGT can be generated via MD using constraints obtained for d(ACGCGU-NA)2. This is demonstrated for unconjugated nalidixic acid and its 6-fluoro derivative. The well-ordered and tightly packed structures thus obtained are compatible with a published model for the quinolone-DNA complex in the active site of gyrases. Molecular details of quinolone-DNA interactions: solution structure of an unusually stable DNA duplex with covalently linked nalidixic acid residues and non-covalent complexes derived from it.,Siegmund K, Maheshwary S, Narayanan S, Connors W, Riedrich M, Printz M, Richert C Nucleic Acids Res. 2005 Aug 26;33(15):4838-48. Print 2005. PMID:16126848 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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