4u92

Crystal structure of a DNA/Ba2+ G-quadruplex containing a water-mediated C-tetrad

spinqualitylabelsall models 4u92, resolution 1.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4u92 is a 2 chain structure with sequence from Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.5Å Ligands: BA, CNV, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed We have determined the 1.50 A crystal structure of the DNA decamer, d(CCACNVKGCGTGG) (CNVK, 3-cyanovinylcarbazole), which forms a G-quadruplex structure in the presence of Ba2+. The structure contains several unique features including a bulged nucleotide and the first crystal structure observation of a C-tetrad. The structure reveals that water molecules mediate contacts between the divalent cations and the C-tetrad, allowing Ba2+ ions to occupy adjacent steps in the central ion channel. One ordered Mg2+ facilitates 3'-3' stacking of two quadruplexes in the asymmetric unit, while the bulged nucleotide mediates crystal contacts. Despite the high diffraction limit, the first four nucleotides including the CNVK nucleoside are disordered though they are still involved in crystal packing. This work suggests that the bulky hydrophobic groups may locally influence the formation of non-Watson-Crick structures from otherwise complementary sequences. These observations lead to the intriguing possibility that certain types of DNA damage may act as modulators of G-quadruplex formation. Crystal structure of a DNA/Ba2+ G-quadruplex containing a water-mediated C-tetrad.,Zhang D, Huang T, Lukeman PS, Paukstelis PJ Nucleic Acids Res. 2014 Nov 11. pii: gku1122. PMID:25389267 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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