Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

1 tiny electron could be key to furture drugs that repair sunburn

26.07.2011
Researchers who have been working for nearly a decade to piece together the process by which an enzyme repairs sun-damaged DNA have finally witnessed the entire process in full detail in the laboratory.

What they saw contradicts fundamental notions of how key biological molecules break up during the repair of sunburn – and that knowledge could someday lead to drugs or even lotions that could heal sunburn in humans.

In the Proceedings of the National Academy of Sciences, the Ohio State University researchers and their colleagues confirm what was previously known about the enzyme photolyase, which is naturally produced in the cells of plants and some animals – though not in mammals, including humans. The enzyme repairs DNA by tearing open the misshapen, damaged area of the DNA in two places and reforming it into its original, undamaged shape.

But the enzyme doesn't break up the injury in both places at once, as researchers previously suspected from theoretical calculations. Instead, it's a two-step process that sends an electron through the DNA molecule in a circuitous route from one breakup site to the other, the new study revealed.

The research was led by Dongping Zhong, the Robert Smith Professor of Physics and professor in the departments of chemistry and biochemistry at Ohio State.

Zhong and his team literally shed light on the process in the laboratory using a laser with a kind of strobe effect to take super-fast measurements of the enzyme in action.

What they saw surprised them.

The two key chemical bond sites broke up one after the other – the first in just a few trillionths of a second, and the next after a 90-trillionths-of-a-second delay.

The reason? The single electron ejected from the enzyme – the source of energy for the breakup – took time and energy to travel from one bond site to the other, tunneling along the outer edge of the ring-shaped damage site.

Also, it turns out that for the enzyme taking the long way around is the most efficient way for the electron to do the job, Zhong explained.

"The enzyme needs to inject an electron into damaged DNA -- but how?" he said. "There are two pathways. One is direct jump from the enzyme across the ring from one side to the other, which is a short distance. But instead the electron takes the scenic route. We found that along the way, there is another molecule that acts as a bridge to speed the electron flow, and in this way, the long route actually takes less time."

Now that they have revealed how the enzyme actually works, the researchers hope that others can use this knowledge to create synthetic photolyase for drugs or even lotions that can repair DNA.

Ultraviolet (UV) light damages DNA by exciting the atoms in the DNA molecule, causing accidental bonds to form between the atoms. The bond is called a photo-lesion, and can lead to a kind of molecular injury called a dimer. Dimers prevent DNA from replicating properly, and cause genetic mutations that lead to diseases such as cancer.

The dimer in question is called a cyclobutane pyrimidine dimer, and it is shaped like a ring that juts out from the side of the DNA.

For those organisms lucky enough to have photolyase in their cells, the enzyme absorbs energy from visible light – specifically, blue light – to shoot an electron into the cyclobutane ring to break it up. The result is a perfectly repaired strand of DNA.

That's why photolyase-carrying insects, fish, birds, amphibians, marsupials, and even bacteria, viruses and yeast are all protected from cancer-causing UV rays from the sun. Meanwhile, humans and all other mammals lack the enzyme, and so are particularly vulnerable to UV.

A synthetic form of photolyase could make up for our enzymatic shortfall. But Zhong's group will leave that discovery to other researchers; they have now set their sights on photoreceptors – the proteins that absorb light and initiate signaling for many biological functions.

This research was funded by the National Institutes of Health, the Packard Foundation, the American Heart Association, and the Ohio State University Pelotonia fellowship.

Coauthors on the paper include Zheyun Liu, Chuang Tan, Xunmin Guo, Ya-Ting Kao, Jiang Li, and Lijuan Wang, all of Ohio State; and Aziz Sancar of the University of North Carolina School of Medicine, Chapel Hill.

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 Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>