Photoactive Ru^II–Polypyridyl Complexes that Display Sequence Selectivity and High‐Affinity Binding to Duplex DNA through Groove Binding

Abstract

The duplex-DNA binding properties of a nonintercalating polypyridyl ruthenium(II) complex that incorporates a linear extended ligand with a catechol moiety has been probed with a variety of photo- and biophysical techniques. These studies reveal that the complex groove binds to DNA sequences biphasically, and displays binding constants equivalent to those of high-affinity metallointercalators. The complex also displays preferential binding to AT-rich sequences. Changes in the structure of the coordinated catechol ligand and the incorporation of intercalating ancillary ligands into the complex were found to modulate both the optical-binding response and binding parameters of the system, which indicates that the catechol moiety plays a crucial role in the observed enhancement to binding affinities.

Synthesis, pH-induced “on–off–on” luminescence switching, and partially intercalative DNA-binding and DNA photocleavage properties of an β-d-allopyranoside-grafted ruthenium(II) complex

“…For example, we have recently observed a 26-fold emission enhancement as [Ru(phen) 2 (cdpq)] + {phen=1,10-phenanthroline, cdpq=deprotonated 2-carboxyldipyrido[3,2-f:2′,3′-h]quinoxaline} groove-bound to DNA [18]. The DNA binding constant values could attain to as high as 2.0 × 10 5 to 2.9 × 10 6 M − 1 equivalent to those of high-affinity metallointercalators, as recently reported by Thomas [19].…”

“…A lot of ruthenium(II) complexes with extended π organic ligands were reported to be classic DNA intercalators, and such structure-property relationships as the effects of the charge, planarity of the intercalative moiety, ancillary ligand, the formation of intramolecular hydrogen bond, and the populations and energies of lowest unoccupied molecular orbital (LUMO) and/or some virtual orbitals near LUMO on the DNA binding properties have been well revealed [18]. But much less is known about structure-property relationships for grooving [18,19] and partially intercalative DNA binders [20][21][22], due mostly to the fact that a very limited number of these two families of DNA binders have been reported. The groove binding of Ru(II) complex to the DNA could be very strong, and could result in evident spectral changes.…”

Photo-induced cytotoxicity and anti-metastatic activity of ruthenium(ii)–polypyridyl complexes functionalized with tyrosine or tryptophan

“…Such changes are not uncommon for reagents that are not bound to DNA structure though intercalative mode of binding. 30,31 Luminescence studies revealed that addition of CT-DNA to the aq. buffer solutions of 1 and 2 led to the enhancement in the fluorescence intensity of the respective complexes.…”

Bioaktive lumineszierende Übergangsmetallkomplexe für biomedizinische Anwendungen

“…[48] Es wurde postuliert, dass die Bindung der Catecholgruppe in die kleine Furche der doppelsträngigen DNA mit Wechselwirkungen zwischen dem Ru II -Zentrum und alternierenden Purin-Pyrimidin-Sequenzen in der kleinen Furche einherging, mit einer besonderen Vorliebe für AT·TA-Abschnitte (K > 10 7 m À1 ). [48] Es wurde postuliert, dass die Bindung der Catecholgruppe in die kleine Furche der doppelsträngigen DNA mit Wechselwirkungen zwischen dem Ru II -Zentrum und alternierenden Purin-Pyrimidin-Sequenzen in der kleinen Furche einherging, mit einer besonderen Vorliebe für AT·TA-Abschnitte (K > 10 7 m À1 ).…”