. Space Industry and Business News .

1 tiny electron could be key to future drugs that repair sunburn
by Staff Writers
Columbus OH (SPX) Jul 29, 2011

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.

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.

Related Links
Ohio State University
Space Technology News - Applications and Research

Get Our Free Newsletters Via Email
Buy Advertising Editorial Enquiries

. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

High levels of caesium found in Fukushima beef
Tokyo (AFP) July 9, 2011
More than six times the legal limit of radioactive caesium has been found in beef from Fukushima prefecture, home to Japan's crippled nuclear plant, an official statement said Saturday. The meat came from one of 11 cows shipped this month to Tokyo from a farmer in Minamisoma city, according to the statement by the Tokyo metropolitan government. The 11 cows all showed high levels of radio ... read more

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

Discovery of a new magnetic order

Apple, Samsung overtake Nokia in smartphone market

Material created at Purdue lets electrons 'dance' and form new state

USAF Approves Production of NGC Deployable Digital Wireless System for Remote Warfighters

Raytheon BBN Technologies Awarded DoD Contract to Develop a Secure, Attributed Military Network System

Northrop Grumman's On-Demand Intelligence System Used for the First Time

Lockheed Martin Team Delivers Joint Tactical Radio to the U.S. Government for Integration into First Aircraft Platform

Russia sends observation satellite into space

NASA inks agreement with maker of Atlas V rocket

Russia launches 2 foreign satellites into orbit

ILS Proton Successfully Launches the SES-3 Satellite for SES

China launches navigation satellite: Xinhua

China to launch 9th orbiter for indigenous global navigation network

Cambridge Pixel, Navtech to work together

Second Boeing GPS IIF Satellite Sends First Signals from Space

Rolls-Royce flies into profit

Embraer plans military transport jet

Boeing Delivers 400th Airplane to GECAS

Israel approves new Eilat international airport

Graphene's 'quantum leap' takes electronics a step closer

Nanoplasmonic Breaks Emission Time Record in Semiconductors

New photonic crystals have both electronic and optical properties

RIM cutting 2,000 jobs, COO retiring

Using Satellites for Human and Environmental Security Needs

Researchers Provide Detailed Picture of Ice Loss Following Collapse of Antarctic Ice Shelves

Aura Detects Pollution in the Great Lakes Region

TerraSAR-X image of the month - Volcanic eruption in Chile

Toxicologists Find Weathered Crude Oil Less Toxic to Bird Eggs

New study finds cancer-causing mineral in US road gravel

Environmental Pollutants Lurk Long After They "Disappear"

EPA to consider BPA testing, research

Memory Foam Mattress Review
Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2011 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement