Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers discover how key enzyme repairs sun-damaged DNA

26.07.2010
Researchers have long known that humans lack a key enzyme -- one possessed by most of the animal kingdom and even plants -- that reverses severe sun damage.

For the first time, researchers have witnessed how this enzyme works at the atomic level to repair sun-damaged DNA.

The discovery holds promise for future sunburn remedies and skin cancer prevention.

In the early online edition of the journal Nature, Ohio State University physicist and chemist Dongping Zhong and his colleagues describe how they were able to observe the enzyme, called photolyase, inject a single electron and proton into an injured strand of DNA. The two subatomic particles healed the damage in a few billionths of a second.

"It sounds simple, but those two atomic particles actually initiated a very complex series of chemical reactions," said Zhong, the Robert Smith Associate Professor of Physics, and associate professor in the departments of chemistry and biochemistry at Ohio State. "It all happened very fast, and the timing had to be just right."

Exactly how photolyases repair the damage has remained a mystery until now.

"People have been working on this for years, but now that we've seen it, I don't think anyone could have guessed exactly what was happening," Zhong said.

He and his colleagues synthesized DNA in the lab and exposed it to ultraviolet light, producing damage similar to that of sunburn, then added photolyase enzymes. Using ultrafast light pulses, they took a series of "snapshots" to reveal how the enzyme repaired the DNA at the atomic level.

Ultraviolet (UV) light damages skin by causing chemical bonds to form in the wrong places along the DNA molecules in our cells.

This study has revealed that photolyase breaks up those errant bonds in just the right spots to cause the atoms in the DNA to move back into their original positions. The bonds are then arranged in such a way that the electron and proton are automatically ejected out of the DNA helix and back into the photolyase, presumably so it could start the cycle over again and go on to heal other sites.

All plants and most animals have photolyase to repair severe sun damage. Everything from trees to bacteria to insects enjoys this extra protection. Only mammals lack the enzyme.

Humans do possess some enzymes that can undo damage with less efficiency. But we become sunburned when our DNA is too damaged for those enzymes to repair, and our skin cells die. Scientists have linked chronic sun damage to DNA mutations that lead to diseases such as skin cancer.

Now that researchers know the mechanism by which photolyase works, they might use that information to design drugs or lotions that heal sun damage, Zhong said.

Normal sunscreen lotions convert UV light to heat, or reflect it away from our skin. A sunscreen containing photolyase could potentially heal some of the damage from UV rays that get through.

Perhaps ironically, photolyase captures light of a different wavelength -- visible light, in the form of photons -- to obtain enough energy to launch the healing electron and proton into the DNA that has been damaged by UV light.

Researchers knew that visible light played a role in the process -- hence the term "photo" in the enzyme's name -- but nobody knew exactly how, until now.

hong's coauthors on the paper include postdoctoral researchers Jiang Li, Xunmin Guo, and Lijuan Wang, and doctoral students Zheyun Liu and Chuang Tan, all of Ohio State; and Aziz Sancar, MD, of the University of North Carolina, Chapel Hill School of Medicine.

This work was funded in part by the National Institutes of Health and the Packard Foundation.

Contact: Dongping Zhong, (614) 292-3044; Zhong.28@osu.edu
Written by Pam Frost Gorder, (614) 292-9475; Gorder.1@osu.edu

Dongping Zhong | EurekAlert!
Further information:
http://www.osu.edu

More articles from Life Sciences:

nachricht Nanoparticle Exposure Can Awaken Dormant Viruses in the Lungs
16.01.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Cholera bacteria infect more effectively with a simple twist of shape
13.01.2017 | Princeton 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: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>