Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Colors and Magnetism

Colors and Magnetism

Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...

Complexation Equilibria: Factors Influencing Stability of Complexes

Complexation Equilibria: Factors Influencing Stability of Complexes

In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...

DNA Topoisomerases

DNA 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. ...

Atomic Nuclei: Nuclear Relaxation Processes

Atomic Nuclei: Nuclear Relaxation Processes

In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.

Microtubule Instability

Microtubule Instability

Microtubules are hollow cylindrical filaments having a diameter of approximately 25 nm and a length that varies from 200 nm to 25 μm. GTP-bound tubulin subunits form αβ-heterodimers for microtubule assembly. These core building blocks interact longitudinally, polymerizing into protofilaments. The protofilaments then interact with one another through lateral bonding forces to form stable cylindrical microtubules. These cylindrical filaments are dynamic as they undergo repeated...

EDTA: Conditional Formation Constant

EDTA: Conditional Formation Constant

Each EDTA molecule has six binding sites: four carboxyl groups and two amino groups. The fully protonated form of EDTA is represented as H6Y2+. However, it can exist in different forms, H5Y+, H4Y, H3Y−, H2Y2−, and HY3−, depending on the pH of the solution. In very basic solutions with pH > 10.17, the fully deprotonated form, Y4−, is the predominant species that readily complexes with metal ions in a 1:1 ratio.
For the equilibrium reaction of the metal with the...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Employing molecular beacons to assess in vitro transcription with single-molecule resolution.

Scientific reports·2026

Same author

Concurrent positional dynamics and activity mapping of DNA-binding proteins.

Nature protocols·2026

Same author

Condensin I but not Condensin II is crucial for mitotic chromosome mechanics.

Nature communications·2026

Same author

Unifying theories in high-dimensional biophysics: approaches, challenges and opportunities.

NPJ systems biology and applications·2026

Same author

A dataset of fine-grained zebrafish interactions in health and disease.

Scientific data·2026

Same author

Mechanistic basis for relaxation of DNA supercoils by human topoisomerase IIIα-RMI1-RMI2.

Proceedings of the National Academy of Sciences of the United States of America·2026

Search research articles

Related Experiment Video

Updated: Mar 18, 2026

Single-Molecule Real-Time Visualization of DNA Unwinding by CMG Helicase

Single-Molecule Real-Time Visualization of DNA Unwinding by CMG Helicase

Published on: September 27, 2024

DNA Twist Stability Changes with Magnesium(2+) Concentration.

Onno D Broekmans¹, Graeme A King¹, Greg J Stephens¹

¹LaserLaB Amsterdam and Department of Physics and Astronomy VU University Amsterdam, 1081 HV Amsterdam, Netherlands.

Physical Review Letters

|July 9, 2016

Summary

This summary is machine-generated.

Ionic conditions significantly impact DNA elasticity. High magnesium ion concentrations stabilize DNA

More Related Videos

Magnetic Tweezers for the Measurement of Twist and Torque

Magnetic Tweezers for the Measurement of Twist and Torque

Published on: May 19, 2014

High-Speed Magnetic Tweezers for Nanomechanical Measurements on Force-Sensitive Elements

High-Speed Magnetic Tweezers for Nanomechanical Measurements on Force-Sensitive Elements

Published on: May 12, 2023

Related Experiment Videos

Last Updated: Mar 18, 2026

Single-Molecule Real-Time Visualization of DNA Unwinding by CMG Helicase

Single-Molecule Real-Time Visualization of DNA Unwinding by CMG Helicase

Published on: September 27, 2024

Magnetic Tweezers for the Measurement of Twist and Torque

Magnetic Tweezers for the Measurement of Twist and Torque

Published on: May 19, 2014

High-Speed Magnetic Tweezers for Nanomechanical Measurements on Force-Sensitive Elements

High-Speed Magnetic Tweezers for Nanomechanical Measurements on Force-Sensitive Elements

Published on: May 12, 2023

Area of Science:

Biophysics
Molecular Biology
Polymer Physics

Background:

Understanding DNA elasticity is crucial for molecular biology.
The wormlike chain model accounts for DNA's helical structure and twist-stretch coupling.
Ionic conditions are known to influence DNA elasticity.

Purpose of the Study:

To systematically measure the effect of buffer ionic conditions on DNA's twist-stretch coupling.
To investigate how ionic strength influences DNA elasticity at high forces.

Main Methods:

Developed a robust fitting approach to analyze DNA elasticity data.
Performed systematic measurements of DNA elasticity under varying ionic conditions.
Utilized high force measurements (F>30 pN) to probe DNA behavior.

Main Results:

DNA's helical twist is stabilized at high concentrations of magnesium divalent cations.
DNA's persistence length and stretch modulus showed relative insensitivity to ionic strength.
The study provides new data on the impact of ionic conditions on twist-stretch coupling.

Conclusions:

Magnesium ion concentration plays a key role in stabilizing DNA's helical twist.
DNA elasticity, particularly persistence length and stretch modulus, is robust to changes in ionic strength within the tested range.
The findings refine models of DNA elasticity under varying physiological conditions.