6rs3

Publication Abstract from PubMed

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 (FrG) analogs. 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 FrG analog 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 FrG analog 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 analogs 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.

Sugar Puckering Drives G-Quadruplex Refolding: Implications for V-Shaped Loops.,Haase L, Dickerhoff J, Weisz K Chemistry. 2019 Oct 14. doi: 10.1002/chem.201904044. PMID:31609483^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.