Tuning i-motif folding and stability with acyclic phosphonate-linked (ZNA) cytidine residues.

ABSTRACT: i-Motifs (iMs) are non-canonical four-stranded DNA structures stabilized by hemi-protonated (C:H⁺C) cytosine base pairs. Under non-acidic pH conditions, cytosine deprotonation disrupts these interactions, resulting in structural unfolding. To broaden the environmental conditions that support iM formation for potential biomedical applications, we investigated the effect of substituting 2'-deoxycytidine residues with either the (R) or (S) isomers of an acyclic phosphonate-linked nucleotide (ZNA) bearing a cytosine (C) or 5-fluorocytosine (5F-C) nucleobase within the 22-mer vertebrate telomeric iM. UV melting and NMR spectroscopy analyses revealed that the presence of ZNA-C in the core of the iM decreased its stability, while 5F-C altered the iM stability across diffe

SUBMITTER: Derden M 

PROVIDER: S-EPMC12501961 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature