The Effect of 2'F-RNA on I-Motif Structure and Stability.

ABSTRACT: I-motifs are non-canonical, cytosine-rich DNA structures stabilized by hemiprotonated C•C⁺ base pairs, whose formation is highly pH-dependent. While certain chemical modifications can enhance i-motif stability, modifications at the sugar moiety often disrupt essential inter-strand contacts. In this study, we examine the structural and thermodynamic impact of incorporating 2'-fluoro-ribocytidine (2'F-riboC) into i-motif-forming sequences derived from d(TCCCCC). Using a combination of UV, ¹H NMR, and ¹⁹F NMR spectroscopy, we demonstrate that full substitution with 2'F-riboC strongly destabilizes i-motif, whereas partial substitutions (one or two substitutions per strand) support well-folded structures at acidic pH (pH 5). High-resolution NMR structures reveal

SUBMITTER: Ugedo C 

PROVIDER: S-EPMC12429874 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature