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

Enzyme Kinetics

Enzyme Kinetics

Enzymes speed up reactions by lowering the activation energy of the reactants. The speed at which the enzyme turns reactants into products is called the rate of reaction. Several factors impact the rate of reaction, including the number of available reactants. Enzyme kinetics is the study of how an enzyme changes the rate of a reaction.
Scientists typically study enzyme kinetics with a fixed amount of enzyme in the controlled environment of a test tube. When more reactant, or substrate, is...

Cooperative Allosteric Transitions

Cooperative Allosteric Transitions

Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...

ATP Synthase: Mechanism

ATP Synthase: Mechanism

In animals, the mitochondrial F1F0 ATP synthase is the key protein that synthesizes ATP molecules through a complex catalytic mechanism. While the nuclear genome encodes the majority of ATP synthase subunits, the mitochondrial genome encodes some of the enzyme's most critical components. The formation of this multi-subunit enzyme is a complex multi-step process regulated at the level of transcription, translation, and assembly. Defects in one or more of these steps can result in decreased ATP...

Cooperative Allosteric Transitions

Cooperative Allosteric Transitions

Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...

Allosteric Proteins-ATCase

Allosteric Proteins-ATCase

Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...

Cooperative Allosteric Transitions

Cooperative Allosteric Transitions

Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...

You might also read

Related Articles

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

Sort by

Same author

Photodynamics of amino acids under UV excitation: Extraterrestrial amino acids.

The Journal of chemical physics·2026

Same author

Development of a Nucleoside Photosensitizer Efficiently Activated by One- or Two-Photon Absorption in the Optical Therapeutic Window.

Journal of the American Chemical Society·2026

Same author

Common Photoproperties of Eumelanin and Natural Organic Matter Emerge from Ensembles of Few-Layered Nanostructures.

ACS central science·2026

Same author

Double Thionation of 4-Dimethylaminophthalimide Leads to the Development of a Highly Effective Photosensitizer.

Chemistry (Weinheim an der Bergstrasse, Germany)·2026

Same author

Impacts of Fluorination at the Ortho-Position of Carboxy Groups on Tetrakis(biphenyl)ethene-Based Hydrogen-Bonded Framework.

Small (Weinheim an der Bergstrasse, Germany)·2026

Same author

Modulating the cytotoxic activity of Titanocene complexes through aliphatic chain modification to optimize albumin affinity.

Bioorganic chemistry·2026

Search research articles

Related Experiment Video

Updated: Jun 17, 2026

Application of Stopped-flow Kinetics Methods to Investigate the Mechanism of Action of a DNA Repair Protein

Application of Stopped-flow Kinetics Methods to Investigate the Mechanism of Action of a DNA Repair Protein

Published on: April 1, 2010

Base stacking controls excited-state dynamics in A.T DNA.

Carlos E Crespo-Hernández¹, Boiko Cohen, Bern Kohler

¹Department of Chemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210, USA.

|August 27, 2005

Summary

DNA photostability is key to preventing mutations from UV light. This study reveals that base stacking, not base pairing, controls excited electronic states in DNA, forming excimers that protect the genetic code.

More Related Videos

Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity

Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity

Published on: August 19, 2013

Structure-Based Simulation and Sampling of Transcription Factor Protein Movements along DNA from Atomic-Scale Stepping to Coarse-Grained Diffusion

Structure-Based Simulation and Sampling of Transcription Factor Protein Movements along DNA from Atomic-Scale Stepping to Coarse-Grained Diffusion

Published on: March 1, 2022

Related Experiment Videos

Last Updated: Jun 17, 2026

Application of Stopped-flow Kinetics Methods to Investigate the Mechanism of Action of a DNA Repair Protein

Application of Stopped-flow Kinetics Methods to Investigate the Mechanism of Action of a DNA Repair Protein

Published on: April 1, 2010

Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity

Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity

Published on: August 19, 2013

Structure-Based Simulation and Sampling of Transcription Factor Protein Movements along DNA from Atomic-Scale Stepping to Coarse-Grained Diffusion

Structure-Based Simulation and Sampling of Transcription Factor Protein Movements along DNA from Atomic-Scale Stepping to Coarse-Grained Diffusion

Published on: March 1, 2022

Area of Science:

Photochemistry
Molecular Biology
Biophysics

Background:

Solar ultraviolet (UV) radiation induces excited electronic states in DNA, potentially leading to mutations.
Enzymatic repair mechanisms counteract DNA photodamage, but are energetically expensive.
DNA's intrinsic photostability is crucial for life, yet the mechanisms of energy dissipation in the double helix are not fully understood.

Purpose of the Study:

To investigate the role of base stacking versus base pairing in the dissipation of electronic energy in DNA.
To elucidate the mechanisms governing the photostability of DNA, particularly in adenine-thymine sequences.

Main Methods:

Studied single- and double-stranded oligonucleotides composed of adenine (A) and thymine (T) bases.
Investigated excited singlet electronic states and their decay pathways.
Analyzed the formation and lifetimes of intrastrand excimer states.

Main Results:

Vertical base stacking, not base pairing, dictates the fate of excited electronic states in DNA oligonucleotides.
Intrastrand excimer states, with lifetimes of 50-150 picoseconds, form readily when adenine bases stack with themselves or thymine.
Excimer formation confines excitation energy to a single strand within the B-form double helix.

Conclusions:

Base stacking is the primary determinant of excited state decay in DNA, facilitating non-radiative energy dissipation.
Excimer formation in DNA protects the genetic material by limiting energy transfer to one strand, allowing the complementary strand to serve as a template for repair.