Download MendeleySugar Puckering Drives G-Quadruplex Refolding: Implications for V-Shaped Loops.
Haase, L., Dickerhoff, J., Weisz, K.(2020) Chemistry 26: 524-533
- PubMed: 31609483
- DOI: https://doi.org/10.1002/chem.201904044
- Primary Citation of Related Structures:
6RS3 - PubMed Abstract:
A DNA G-quadruplex adopting a (3+1) hybrid structure was modified in two adjacent syn positions of the antiparallel strand with anti-favoring 2'-deoxy-2'-fluoro-riboguanosine ( F rG) analogues. The two substitutions promoted a structural rearrangement to a topology with the 5'-terminal G residue located in the central tetrad and the two modified residues linked by a V-shaped zero-nucleotide loop. Strikingly, whereas a sugar pucker in the preferred north domain is found for both modified nucleotides, the F rG analogue preceding the V-loop is forced to adopt the unfavored syn conformation in the new quadruplex fold. Apparently, a preferred C3'-endo sugar pucker within the V-loop architecture outweighs the propensity of the F rG analogue to adopt an anti glycosidic conformation. Refolding into a V-loop topology is likewise observed for a sequence modified at corresponding positions with two riboguanosine substitutions. In contrast, 2'-F-arabinoguanosine analogues with their favored south-east sugar conformation do not support formation of the V-loop topology. Examination of known G-quadruplexes with a V-shaped loop highlights the critical role of the sugar conformation for this distinct structural motif.
Organizational Affiliation:
Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany.
