Scroll down to see the video in action. The enzyme (lower left) attaches to and manipulates the string of DNA during the video. The study could provide a model for understanding how human enzymes and DNA interact.
Credit: BBSRC/PNAS
SYDNEY: For the first time, scientists have captured remarkable footage of the nanoscale interaction of an enzyme and a strand of DNA.
Researchers from the University of Cambridge in the U.K. used an incredibly high resolution scanning atomic force microscope to produce footage of the protective enzyme of a bacterial host unravelling the DNA of an attacking virus.
"This is the first time that such a process has been seen in real time. To be able see these nano-mechanisms as they are really happening is incredibly exciting," said Robert Henderson, lead researcher behind the feat. "We can actually see the enzyme 'threading' through a loop in the virus's DNA in order to lock on to and break it, a process known as DNA cleavage."
The DNA in the video is one nanometre wide; that is approximately one million times narrower than the head of a pin.
State-of-the-art technique
Working with an international team, the University of Cambridge team used the state-of-the-art microscope housed at a Japanese institute – one of only three in the world – and a technique called 'fast scan' atomic force microscopy. Before now, researchers could only make assumptions as to how proteins and DNA interacted based on indirect evidence, but this technique gives them a new window on a fundamental biological process.
"Standard technology for filming on this scale can only produce one image frame every 8 minutes," said Henderson. "However, our new work allows one frame per 500, or fewer, milliseconds."
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The footage shows a bacterial restriction enzyme attaching itself to the DNA of a virus, in order to break the DNA before the virus has the chance to infect the bacterium. (Credit:BBSRC/PNAS).
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Aside from just being cool, the researchers argue that the video could help advance understanding of how enzymes attach to and repair DNA – which could potentially have applications in cancer preventatives or treatments.
The research was announced yesterday by the U.K.'s Biotechnology and Biological Sciences Research Council and was reported in a recent issue of the U.S. journal the Proceedings of the National Academy of Sciences.
with the BBSRC
