The effect of the neutral cytidine protonated analogue pseudoisocytidine on the stability of i-motif structures

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 locate...

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Bibliographic Details
Main Authors: B. Mir, X. Solés, C. González, N. Escaja
Format: article
Language:EN
Published: Nature Portfolio 2017
Subjects:
R
Q
Online Access:https://doaj.org/article/b288ee1eb6af4dbaae3b1e08d253ca64
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Summary: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.