# name
pH-Dependent Capping Interactions Induce Large-Scale Structural Transitions in i-Motifs

# metadata.dc.description.abstract[].value
We study here a DNA oligonucleotide having the ability to form two
different i-motif structures whose relative stability depends on pH and temperature. The major species at neutral pH is stabilized by two C:C+ base pairs capped by two minor groove G:C:G:C tetrads. The high pH and thermal stability of this structure are mainly due to the favorable effect of the minor groove tetrads on their adjacent positively charged C:C+ base pairs. At pH 5, we observe a more elongated i-motif structure consisting of four C:C+ base pairs capped by two G:T:G:T tetrads. Molecular dynamics calculations show
that the conformational transition between the two structures is driven by the protonation state of key cytosines. In spite of large conformational differences, the transition between the acidic and neutral structures can occur without unfolding of the i-motif. These results represent the first case of a conformational switch between two different i-motif structures and illustrate the dramatic pH-dependent plasticity of this fascinating DNA motif.

# metadata.dc.relation.ispartof[].value
Journal of the American Chemical Society, 2023, vol. 145, num. 6, p. 3696–3705

# metadata.dc.rights[].value
cc by (c) Serrano Chacón, Israel et al., 2023

# metadata.dc.source[].value
Articles publicats en revistes (Institut de Recerca Biomèdica (IRB Barcelona))

# metadata.dc.title[].value
pH-Dependent Capping Interactions Induce Large-Scale Structural Transitions in i-Motifs