[ExI] Video shows real enzyme-DNA interaction

[Damien Broderick]

http://www.cosmosmagazine.com/node/1588

[vid link on the site above]

Video shows real enzyme-DNA interaction

Tuesday, 18 September 2007
Cosmos Online

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."