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Tuning the pH Response of i‐Motif DNA Oligonucleotides
Author(s) -
Lannes Laurie,
Halder Saheli,
Krishnan Yamuna,
Schwalbe Harald
Publication year - 2015
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201500182
Subject(s) - destabilisation , oligonucleotide , chemistry , motif (music) , dna , structural motif , cytosine , biophysics , stereochemistry , crystallography , combinatorial chemistry , biochemistry , biology , psychology , social psychology , physics , acoustics
Cytosine‐rich single‐stranded DNA oligonucleotides are able to adopt an i‐motif conformation, a four‐stranded structure, near a pH of 6. This unique pH‐dependent conformational switch is reversible and hence can be controlled by changing the pH. Here, we show that the pH response range of the human telomeric i‐motif can be shifted towards more basic pH values by introducing 5‐methylcytidines (5‐MeC) and towards more acidic pH values by introducing 5‐bromocytidines (5‐BrC). No thermal destabilisation was observed in these chemically modified i‐motif sequences. The time required to attain the new conformation in response to sudden pH changes was slow for all investigated sequences but was found to be ten times faster in the 5‐BrC derivative of the i‐motif.