Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

’Pinball protons’ created by ultraviolet rays and other causes can lead to DNA damage

19.05.2006
Researchers have known for years that damaged DNA can lead to human diseases such as cancer, but how damage occurs--and what causes it--has remained less clear.

Now, computational chemists at the University of Georgia have discovered for the first time that when a proton is knocked off one of the pairs of bases that make up DNA, a chain of damage begins that causes "lesions" in the DNA. These lesions, when replicated in the copying mechanisms of DNA, can lead to serious disorders such as cancer.

The research, just published in the Proceedings of the National Academy of Sciences (PNAS), was led by doctoral student Maria Lind and Henry F. Schaefer III, Graham-Perdue Professor of Chemistry. Other authors on the paper are doctoral student Partha Bera, postdoctoral associate Nancy Richardson and recent doctoral graduate Steven Wheeler.

Call it a "pinball proton." While chemists have shown other causes of DNA damage, the report in PNAS is the first to report how protons, knocked away by such mechanisms as radiation or chemical exposure, can cause lesions in DNA. The work was done entirely on computers in the Center for Computational Chemistry, part of the Franklin College of Arts and Sciences at UGA.

"This kind of damage in DNA subunits is about as basic as you can get," said Schaefer. "This is the simplest kind of lesion possible for such a system."

The double-helix structure of DNA has been known for more than half a century. This basic building block of life can "unzip" itself to create copies, a process at the heart of cell replication and growth. DNA is made of four "bases," Adenine, Guanine, Thymine and Cytosine, and each one pairs with its opposite to form bonds where the "information" of life is stored. Thus, Guanine pairs with Cytosine, and Thymine with Adenine.

The team at the University of Georgia studied how the removal of a proton from the Guanine-Cytosine (G-C) base pair is involved in creating lesions that can lead to replication errors. This pair has 10 protons, meaning there are numerous targets for processes that knock the protons off.

The lesions are breaks in the hydrogen bonds, of which there are two in the G-C base pair. (The Adenine-Thymine pair has three hydrogen bonds.)

"Our real goal is to examine all possible lesions in DNA subunits," said Lind.

The team discovered that the base pair minus its knocked-off proton can either break entirely or change its bonding angle--something that also causes improper replication.

"The C-G subunit is usually totally planar [flat]," said Lind. "If it twists, it could simply pull apart."

Though it has already been suspected that lesions in DNA caused by both high- and low-energy electrons result in cancer cell formation, the new study is the first evidence that protons do the same thing.

The study in PNAS also has other implications. Researchers are beginning to understand how DNA can be used as "molecular wire" in constructing electrical circuits. Such a breakthrough would allow small electronic devices to shrink even further, but how the electrical properties of DNA would work in such a context is not yet understood. The UGA research adds important knowledge about how so-called "deprotonated" DNA base pairs work and could be important in creating "DNA wire."

Kim Carlyle | EurekAlert!
Further information:
http://www.uga.edu

More articles from Life Sciences:

nachricht 'Y' a protein unicorn might matter in glaucoma
23.10.2017 | Georgia Institute of Technology

nachricht Microfluidics probe 'cholesterol' of the oil industry
23.10.2017 | Rice University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Salmonella as a tumour medication

HZI researchers developed a bacterial strain that can be used in cancer therapy

Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Microfluidics probe 'cholesterol' of the oil industry

23.10.2017 | Life Sciences

Gamma rays will reach beyond the limits of light

23.10.2017 | Physics and Astronomy

The end of pneumonia? New vaccine offers hope

23.10.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>