Researchers from Western University have discovered a protein that exhibits the never-before-seen capability of neutralizing DNA damage while it is happening.
The protein, called DdrC, was found in a common bacterium called Deinococcus radiodurans which can survive conditions that damage DNA as well as repair the DNA that has already been damaged.
While every cell has mechanisms to repair DNA, DdrC excels at it. "With a human cell, if there are any more than two breaks in the entire billion base pair genome, it can't fix itself and it dies," said Szabla, a grad student in Western's Department of Biochemistry.. "But in the case of DdrC, this unique protein helps the cell to repair hundreds of broken DNA fragments into a coherent genome."
In the research, published in Nucleic Acids Research, the researchers utilized the Canadian Light Source (CLS) to resolve the 3D shape of the protein to assist in better understanding its ability to neutralize DNA damage.
Ultimately the team discovered the DdrC scans for breaks along its DNA and once a break is found, it snaps shut. "It neutralizes it (the DNA damage), and prevents the break from getting damaged further. And it acts like a little molecular beacon. It tells the cell 'Hey, over here. There's damage. Come fix it," added Szabla.
Curious as to whether the protein may work as a “plug-in” for other repair systems, the team added it to E. coli. "To our huge surprise, it actually made the bacterium over 40 times more resistant to UV radiation damage," said Szabla. "This seems to be a rare example where you have one protein and it really is like a standalone machine."
"The ability to rearrange and edit and manipulate DNA in specific ways is the holy grail in biotechnology," says Szabla. "What if you had a scanning system such as DdrC which patrolled your cells and neutralized damage when it happened? This might form the basis of a potential cancer vaccine."
"DdrC is just one out of hundreds of potentially useful proteins in this bacterium. The next step is to prod further, look at what else this cell uses to fix its own genome—because we're sure to find many more tools where we have no idea how they work or how they're going to be useful until we look," he added.