Related Experiment Video
Updated: Jul 16, 2026
11:27
Single-Molecule Förster Resonance Energy Transfer Methods for Real-Time Investigation of the Holliday Junction Resolution by GEN1
Published on: September 18, 2019
Triple-helix mediated excimer and exciplex formation
1Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
Bioconjugate Chemistry
|February 21, 2007
Summary
Researchers created novel triple-helical hybrids using non-nucleosidic polyaromatic compounds. These structures demonstrate enhanced stability and fluorescence properties, paving the way for new molecular tools.
Area of Science:
- Supramolecular Chemistry
- Oligonucleotide Chemistry
Background:
- Triple helices are DNA structures with potential applications in diagnostics and therapeutics.
- Incorporating non-nucleosidic building blocks offers a route to modify oligonucleotide properties.
- Polyaromatic moieties can influence stacking interactions and photophysical behavior.
Purpose of the Study:
- To synthesize and characterize triple-helical hybrids incorporating non-nucleosidic polyaromatic building blocks.
- To investigate the stability of these hybrids with complementary polypurine target strands.
- To explore the fluorescence properties arising from excimer or exciplex formation.
Main Methods:
- Synthesis of clamp-type oligonucleotides with pyrene linkers.
- Hybridization with polypurine target strands containing pyrene or phenanthrene.
- Stability assessment through biophysical techniques.
- Fluorescence spectroscopy to monitor excimer/exciplex formation.
Main Results:
- Stable triple helices were formed between pyrene-containing oligonucleotides and polypurine targets.
- Non-nucleosidic pyrene and phenanthrene moieties enhanced triplex stability through stacking interactions.
- Strong excimer and exciplex formation was observed and quantified via fluorescence spectroscopy.
Conclusions:
- Non-nucleosidic polyaromatic building blocks can be successfully integrated into triple-helical structures.
- These modified triplexes exhibit enhanced stability and unique photophysical properties.
- The findings support the development of novel oligonucleotide-based systems for molecular recognition and sensing.
Related Concept Videos
01:08Nucleotide Excision Repair
Overview
01:38Nucleotide Excision Repair
DNA Distortion and Damage
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
02:31Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
01:26Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
01:54Base Excision Repair
One of the common DNA damages is the chemical alteration of single bases by alkylation, oxidation, or deamination. The altered bases cause mispairing and strand breakage during replication. This type of damage causes minimal change to the DNA double helix structure and can be repaired by the base excision repair (BER) pathways. BER corrects damaged DNA sequences by removing the damaged base and restoring the original base sequence using the complementary strand as a template.
The first step of...
The first step of...
01:26Protein Modifications in the RER
Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.