The effect of the neutral cytidine protonated analogue pseudoisocytidine on the stability of i-motif structures.
Mir, B., Soles, X., Gonzalez, C., Escaja, N.(2017) Sci Rep 7: 2772-2772
- PubMed: 28584239 
- DOI: https://doi.org/10.1038/s41598-017-02723-y
- Primary Citation of Related Structures:  
5NIP - PubMed Abstract: 
Incorporation of pseudoisocytidine (psC), a neutral analogue of protonated cytidine, in i-motifs has been studied by spectroscopic methods. Our results show that neutral psC:C base pairs can stabilize i-motifs at neutral pH, but the stabilization only occurs when psC:C base pairs are located at the ends of intercalated C:C + stacks. When psC occupies central positions, the resulting i-motifs are only observed at low pH and psC:C + or psC:psC + hemiprotonated base pairs are formed instead of their neutral analogs. Overall, our results suggest that positively charged base pairs are necessary to stabilize this non-canonical DNA structure.
Organizational Affiliation: 
Inorganic and Organic Chemistry Department, Organic Chemistry Section, and IBUB, University of Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Spain.