Are i‐Motif Structures in DNA Compatible with Cytosine–Ag(I)–Cytosine Base Pairs?
Abstract
Abstract To evaluate whether the protons of hemi‐protonated C:CH + base pairs in DNA i‐motif structures can be replaced by silver ions, an i‐motif/duplex junction (IDJ) known to be stable at pH 7 was investigated. Interestingly, only the most accessible out of five C:CH + pairs in the structure can be converted into a C–Ag I –C base pair, as was derived by 1 H NMR spectroscopy, luminescence spectroscopy, temperature‐dependent UV spectroscopy, and isothermal titration calorimetry (ITC). When more than one silver ion is present per IDJ, dynamic light scattering (DLS) and CD spectroscopy indicate that the IDJ rearranges into a larger aggregated structure, likely to contain non‐canonical silver‐mediated base pairs. The study suggests that—in contrast to earlier reports—the DNA i‐motif in general is not compatible with the formation of contiguous C–Ag I –C pairs.
Article Details
Authors (9)
Victoria Seiffert
Institut für Anorganische und Analytische Chemie Universität Münster Corrensstr. 28/30 48149 Münster Germany
Carmen López‐Chamorro
Departamento de Química Inorgánica Unidad de Excelencia Química Aplicada a Biomedicina y Medioambiente Facultad de Ciencias Universidad de Granada Avda Fuentenueva s/n Granada 18071 Spain
Miquel Barceló‐Oliver
Departament de Química Universitat de les Illes Balears carretera Valldemossa km 7.5, Ed. Mateu Orfila i Rotger Palma de Mallorca 07122 Spain
Catharina Erbacher
Institut für Anorganische und Analytische Chemie Universität Münster Corrensstr. 48 48149 Münster Germany
Uwe Karst
Marian Hebenbrock
Institut für Anorganische und Analytische Chemie Universität Münster Corrensstr. 28/30 48149 Münster Germany
Heinz‐Bernhard Kraatz
Department of Physical and Environmental Sciences University of Toronto Scarborough 1265 Military Trail Toronto M1C 1A4 Canada
Miguel A. Galindo
Departamento de Química Inorgánica Unidad de Excelencia Química Aplicada a Biomedicina y Medioambiente Facultad de Ciencias Universidad de Granada Avda Fuentenueva s/n Granada 18071 Spain
Jens Müller