Download MendeleyDNA-RNA Hybrid Quadruplexes Reveal Interactions that Favor RNA Parallel Topologies.
Haase, L., Dickerhoff, J., Weisz, K.(2018) Chemistry 24: 15365-15371
- PubMed: 30084512
- DOI: https://doi.org/10.1002/chem.201803367
- Primary Citation of Related Structures:
6FFR - PubMed Abstract:
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-H⋅⋅⋅O 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.
Organizational Affiliation:
Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany.
