Amazing stuff! "Research could lead to cancer vaccines and drought-resistant crops"
"Researchers ... have discovered a protein that has the never-before-seen ability to stop DNA damage in its tracks. The finding could provide the foundation for developing everything from vaccines against cancer, to crops that can withstand the increasingly harsh growing conditions brought on by climate change. ..."
"... The researchers found the protein—called DdrC (for DNA Damage Repair Protein C) - in a fairly common bacterium called Deinococcus radiodurans (D. radiodurans), which has the decidedly uncommon ability to survive conditions that damage DNA - for example, 5,000 to 10,000 times the radiation that would kill a regular human cell. Lead researcher ... says Deinococcus also excels in repairing DNA that has already been damaged. ...
team used the Canadian Light Source (CLS) at the University of Saskatchewan (USask) ...
team used the Canadian Light Source (CLS) at the University of Saskatchewan (USask) ...
Turns out that DdrC scans for breaks along the DNA and when it detects one it snaps shut - like a mousetrap. This trapping action has two key functions. He explains, "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.'" ...
They tested this by adding it to a different bacterium: E. coli. "To our huge surprise, it actually made the bacterium over 40 times more resistant to UV radiation damage," he says. "This seems to be a rare example where you have one protein and it really is like a standalone machine." ..."
From the abstract:
"The bacterium Deinococcus radiodurans is known to survive high doses of DNA damaging agents. This resistance is the result of robust antioxidant systems which protect efficient DNA repair mechanisms that are unique to Deinococcus species. The protein DdrC has been identified as an important component of this repair machinery. DdrC is known to bind to DNA in vitro and has been shown to circularize and compact DNA fragments. The mechanism and biological relevance of this activity is poorly understood. Here, we show that the DdrC homodimer is a lesion-sensing protein that binds to two single-strand (ss) or double-strand (ds) breaks. The immobilization of DNA breaks in pairs consequently leads to the circularization of linear DNA and the compaction of nicked DNA. The degree of compaction is directly proportional with the number of available nicks. Previously, the structure of the DdrC homodimer was solved in an unusual asymmetric conformation. Here, we solve the structure of DdrC under different crystallographic environments and confirm that the asymmetry is an endogenous feature of DdrC. We propose a dynamic structural mechanism where the asymmetry is necessary to trap a pair of lesions. We support this model with mutant disruption and computational modeling experiments."
Newly discovered protein stops DNA damage (original news release)
Graphical abstract
Fig. 2 Characterization of the interactions between DdrC and single-strand breaks.
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