Regensburg 2010 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 3: DNA, RNA and Associated Enzymes

BP 3.4: Vortrag

Montag, 22. März 2010, 15:00–15:15, H43

Human Telomeric Quadruplex Conformations studied by pulse EPR — Mykhailo Azarkh, Singh Vijay, Hartig Jörg, and •Drescher Malte — University of Konstanz, 78457 Konstanz, Germany

The Emmy-Noether group at the department of Physical Chemistry in Konstanz is engaged in developing and applying methods in Electron Paramagnetic Resonance (EPR) to study structure and dynamics of disordered materials.

Here we present for the first time distance measurements in quadruplex sequences based on pulsed EPR measurements (DEER) of double-nitroxide spin labeled DNA oligonucleotides. Telomeric quadruplex sequences have attracted much attention since a biological function of these unusual folds is anticipated. The human telomeric repeat is able to form structures that differ drastically in strand orientation and loop connectivity. Although it has been an important quest to decipher the physiologically relevant quadruplex topologies, the exact structures contributing to the mixtures present in potassium-rich solutions are still discussed controversially.

Our measurements demonstrate the presence of the all-parallel (so called propeller) and the all-anti-parallel (called basket) conformation in K+ solution, adding an important piece of evidence to the current debate.