Model of a tetramolecular quadruplex DNA with five ammonium ions embedded within the central cavity and the corresponding electrospray mass spectrum showing the peak of the intact assembly.
Guanine-rich sequences which are able to form tetraplex structures are found in telomere regions of many organisms, e.g. yeasts, ciliate protozoa, and human. Quadruplex DNA attracted notice as they are believed to maintain regulatory functions of cell cycle control, thus, also acting as a potential target for chemotherapeutic approaches. Increased activity in this field demands precise and fast analytical tools for structural elucidation of noncovalently bound quadruplex structures.

This work was carried out by Silvan Stucki and Adrien Nyakas in the group of PD Dr. Stefan Schürch.

References:

• S. R. Stucki, A. Nyakas and S. Schürch;
  "Tandem Mass Spectrometry of Platinated Quadruplex DNA"
  J. Mass. Spectrom., 46, 1288–1297, (2011); doi:10.1002/jms.2019.