Metallointercalation Reagents. 2-Hydroxyethanethiolato(2,2′,2″-terpyridine)-platinum(II) Monocation Binds Strongly to DNA By Intercalation

Abstract

The red, cationic complex 2-hydroxyethanethiolato(2,2',2"-terpyridine)platinum(II), [(terpy)-Pt(SCH2CH20H)J+, binds strongly to DNA by a mechanism involving intercalation. By means of fluorescence spectroscopy, the platinum complex was shown to inhibit competitively the binding of the intercalating dye ethidium bromide to calf thymus DNA. This platinum complex increases the viscosity of calf thymus DNA, raises the melting temperature by up to 5°, and exhibits induced circular dichroism when bound to the DNA. The closed circular viral DNA from bacteriophage PM2 is unwound by the complex in a manner that is similar to that of ethidium bromide and with an unwinding angle that appears to be slightly less than that of ethidium. Studies of the related complex [(terpy)PtCll+, which has a substitutionally more labile chloride ligand, suggest that it also intercalates, especially at [DNA-PJ: [PtI ratios greater than 2. The potential utility of these new metallointercalation reagents as heavy atom probes in fiber diffraction or electron microscopic studies of the interaction process is discussed.

4‐Picoline‐2,2′:6′,2″‐terpyridine‐platinum(II) — A potent intercalator of DNA

“…2,2': 6',2"-Terpyridine-platinum(II) complexes were first reported to bind to ds DNA by intercalation over twenty years ago, the duplex unwinding angle being comparable to that found with ethidium bromide [1]. An investigation of the binding of hydroxyethanethiol-2,2': 6',2"-terpyridine-platinum(II) 1 (R --SCH2CH2OH ) with calf-thymus (ct)-DNA by fiber X-ray diffraction techniques showed the platinum ions in the complex to be distributed along the helix axis in accord with the nearest neighbour exclusion model [2].…”

Synthesis and preliminary DNA-binding studies of diimineplatinum(ii) complexes containing 3- or 4-pyridineboronic acid

“…The product was recrystallised by careful diffusion of diethyl ether into a methanol solution of 3, filtered off and then dried in vacuo (0.210 g, 71%). 1 …”

“…1 Recently, the DNA intercalation of platinum(II) complexes containing bidentate diimines such as 2,2 -bipyridine (bipy), 1,10-phenanthroline (phen) and dipyrido[3,2-a:2 ,3 -c]phenazine (dppz), has also been thoroughly investigated and the complexes have all exhibited strong affinities toward DNA. 2-6 Related complexes containing a closothioalkylcarborane ligand and a platinum(II)-terpy unit or chelating diimine ligands such as bipy and phen were reported as potential DNA metallointercalators for boron neutron capture therapy (BNCT).…”

Fluorescent Labeling of Plasmid DNA and mRNA: Gains and Losses of Current Labeling Strategies

“…Around the same time, 25 Ernst Abbe published his theoretical analysis of the role of diffraction in optical microscopy 2 . 26 It was however only at the start of the 20 th century that a prototype of a bright field fluorescence 27 microscope was built at the Carl Zeiss factory. Continuous instrumentation development and 28 fluorescent probe design was conducted over the next 50 years and with the invention of the 29 beam splitting plate (dichroic mirror) 3 , the basis of the fluorescence microscope as we know it 30 today was formed 4, 5 .…”

“…TdT has 24 the strongest affinity for single-stranded DNA or the 3' overhang of double-stranded DNA and 25 is used frequently for adding modified dNTPs to PCR primers or restriction enzyme generated 26 3' overhangs (see Figure 1 C) 54,55 . An example is the 3' EndTag DNA end labeling kit from 27 Vectorlabs, which couples SH-GTP to the 3' end of DNA molecules. The SH-GTP can 28 subsequently be modified with thiol-reactive molecules such as for example maleimide-coupled 29 dyes.…”