For the first time, scientists have been able to observe in real time the interaction between an enzyme and its DNA target. The findings could have implications for research on cancer, which can occur when enzymes fail to repair damaged DNA.
Using a technique known as fast-scan atomic force microscopy (AFM), researchers from Edinburgh, Japan, India, and Cambridge, U.K., filmed a bacterial enzyme attaching to the DNA of a virus trying to infect the bacterium.
In a press release on the research from the Biotechnology and Biological Sciences Research Council, which funded the work, lead researcher Robert Henderson explains,
“This is the first time that such a process has been seen in real time. To be able [to] see these nano-mechanisms as they are really happening is incredibly exciting. 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 microscope and new techniques give us a clear view of the molecular interactions between proteins and DNA that we could only previously interpret indirectly. The indirect methods require scientists to make assumptions to interpret their data, and video footage like this can help to provide a more direct understanding of what is really happening.
“Standard technology for filming on this scale can only produce one image frame every 8 minutes. However, our new work allows one frame per 500–or fewer, milliseconds.
“This helps us understand how enzymes recognise which bit of a DNA strand to latch onto, which is important in understanding how proteins repair damaged DNA. In the long term, this could help in the search for cancer treatments, as cancer sometimes occurs where DNA is damaged but enzymes do not behave correctly in order to repair it.”