6ffr

DNA-RNA Hybrid Quadruplex with Flipped Tetrad

spinqualitylabelsall models 6ffr, 10 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6ffr is a 1 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed A DNA G-quadruplex adopting a (3+1)-hybrid structure was substituted at its 5'-tetrad by riboguanosine (rG) analogs. Incorporation of anti-favoring rG at appropriate syn-positions of the 5'-outer tetrad induced conformational rearrangements to yield a quadruplex featuring a 5'-tetrad with reversed polarity. A high-resolution structure of a disubstituted quadruplex variant as well as direct NMR experimental evidence reveals a non-conventional C-HO hydrogen bond in a medium groove between the 2'-OH of an rG residue adopting a C2'-endo sugar pucker and H8 of a 3'-neighboring anti-G residue. In contrast, a C3'-endo sugar conformation for another guanine ribonucleotide prevents formation of a corresponding hydrogen bond but relocates its 2'-OH substituent from the quadruplex narrow groove into a medium groove. Both the formation of favorable CHO hydrogen bridges and unfavorable interactions of the 2'-hydroxyl group in a narrow groove will promote RNA folding into a parallel topology featuring all-anti core residues and four grooves of medium size. DNA-RNA Hybrid Quadruplexes Reveal Interactions that Favor RNA Parallel Topologies.,Haase L, Dickerhoff J, Weisz K Chemistry. 2018 Aug 7. doi: 10.1002/chem.201803367. PMID:30084512 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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