Related Experiment Video
Updated: May 22, 2026
07:41
Sequential Salt Extractions for the Analysis of Bulk Chromatin Binding Properties of Chromatin Modifying Complexes
Published on: October 2, 2017
The effect of Se salts on DNA structure
Shohreh Nafisi1, Maryam Montazeri, Firouzeh Manouchehri
1Department of Chemistry, Islamic Azad University, Central Tehran Branch (IAUCTB), Tehran 14676-86831, Iran. drsnafisi@yahoo.com
Summary
Selenium compounds like sodium selenite and sodium selenate bind to DNA, potentially impacting cancer prevention. While high concentrations cause DNA aggregation, the DNA structure remains stable.
Area of Science:
- Biochemistry
- Molecular Biology
- Toxicology
Background:
- Selenium compounds are investigated for their antioxidant properties and role in cancer prevention.
- Understanding the interaction between selenium and DNA is crucial for evaluating its biological effects.
Purpose of the Study:
- To investigate the binding modes, constants, and stability of selenium-DNA complexes.
- To determine the impact of sodium selenite (Na(2)SeO(3)) and sodium selenate (Na(2)SeO(4)) on DNA structure and stability.
Main Methods:
- Fourier transform infrared (FTIR) spectroscopy.
- UV-Visible spectroscopy.
- Analysis of binding constants and DNA aggregation.
Main Results:
- Na(2)SeO(4) and Na(2)SeO(3) bind to DNA grooves and the phosphate backbone.
- Binding constants were determined: K(Na(2)SeO(4)-DNA)=5.20×10(4) M⁻¹ and K(Na(2)SeO(3)-DNA)=1.87×10(3) M⁻¹.
- DNA aggregation observed at high selenium concentrations; DNA maintained B-family structure without conformational changes.
Conclusions:
- Selenium compounds interact with DNA through groove and backbone binding.
- The binding affinity differs between sodium selenate and sodium selenite.
- Selenium interactions with DNA do not induce significant structural alterations, suggesting a stable DNA conformation.
Related Concept Videos
01:03Single-Strand DNA Binding Proteins
For successful DNA replication, the unwinding of double-stranded DNA must be accompanied by stabilization and protection of the separated single strands of the DNA. This crucial task is performed by single-strand DNA-binding (SSB) proteins. They bind to the DNA in a sequence-independent manner, which means that the nitrogenous bases of the DNA need not be present in a specific order for binding of SSB proteins to it. The binding of SSB proteins straightens single-stranded DNA (ssDNA) and makes...
02:04Fixing Double-strand Breaks
The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...
02:25Overview of DNA Repair
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
01:19Ionic Strength: Effects on Chemical Equilibria
The addition of an inert ionic compound increases the solubility of a sparingly soluble salt. For example, adding potassium nitrate to a saturated solution of calcium sulfate significantly enhances the solubility of calcium sulfate. Le Châtelier's principle cannot predict this shift in the equilibrium. Instead, this could be explained in terms of changes in the effective concentration of the ions in solution in the presence of added inert salt.
In this solution, the primary cation—the calcium...
In this solution, the primary cation—the calcium...
02:02DNA Topoisomerases
Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
01:05Maxam-Gilbert Sequencing
In the same year as the discovery of the Sanger sequencing method, another group of scientists, Allan Maxam and Walter Gilbert, demonstrated their chemical-cleavage method for DNA sequencing. The Maxam-Gilbert method relies on using different chemicals that can cleave the DNA sequence at specific sites, the separation of resulting DNA fragments of variable size using electrophoresis, and deciphering the DNA sequence from the resulting gel bands.
Challenges of the Maxam-Gilbert Method
The...
Challenges of the Maxam-Gilbert Method
The...