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

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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."

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.