Promoting the formation and stabilization of G-quadruplex by dinuclear RuII complex Ru2(obip)L4.

Area of Science:

• Coordination Chemistry
• Biophysical Chemistry
• Molecular Biology

Background:

• G-quadruplexes are crucial DNA structures involved in telomere maintenance.
• Stabilization of G-quadruplexes is a target for therapeutic interventions.
• Ruthenium(II) complexes are explored for their DNA-binding and G-quadruplex interacting properties.

Purpose of the Study:

• To investigate the ability of a new dinuclear Ruthenium(II) complex, Ru2(obip)L4, to promote and stabilize human telomeric G-quadruplexes.
• To elucidate the binding mode and stoichiometry of the complex with the G-quadruplex.

Main Methods:

• Thermal denaturation (Tm) studies to assess stabilization.
• Luminescence-based Job plot analysis to determine binding stoichiometry.
• Spectroscopic methods to characterize complex-G-quadruplex interactions.

Main Results:

• Ru2(obip)L4 induces the formation of an antiparallel G-quadruplex structure.
• The complex significantly increases the melting temperature (Tm) of the G-quadruplex in the presence of Na+ and K+ ions.
• A 1:1 binding stoichiometry between Ru2(obip)L4 and the G-quadruplex was determined, suggesting specific interaction with a guanine tetrad.

Conclusions:

• The dinuclear Ru(II) complex Ru2(obip)L4 is a potent inducer and stabilizer of human telomeric G-quadruplex DNA.
• The complex exhibits specific binding to the G-quadruplex, likely through interaction with a guanine tetrad.
• This finding highlights the potential of Ru2(obip)L4 as a tool for studying and potentially targeting G-quadruplex structures.