Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

One Tiny Electron Could Be Key to Future Drugs that Repair Sunburn

27.07.2011
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

Pam Frost Gorder | Newswise Science News
Further information:
http://www.osu.edu

Further reports about: DNA DNA molecule Dongping Electron Tiny plants biological function drugs genetic mutation repair sunburn

More articles from Life Sciences:

nachricht Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY

nachricht NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

NSF-supported researchers to present new results on hurricanes and other extreme events

19.07.2018 | Earth Sciences

Scientists uncover the role of a protein in production & survival of myelin-forming cells

19.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>