Apr 19, 2013
A real-time view onto the rules of life
An enzyme marked with fluorescent nanoparticles surfs between two marker sequences (gray triangles) on a DNA molecule that is stretched in magnetic tweezers. This is made visible with a laser microscope. If the marker is missing on both DNA sequences, the defense against a virus attack is initiated.
Naturally occurring bacteria and viruses are in a constant struggle for existence among each other. Bacteria developed a kind of immune system in order to protect themselves from virus attacks: Special defense enzymes can destroy the viral genetic information (DNA) and at the same time assure that the DNA of the bacterium isn’t attacked. In this process involved are markers on the DNA of the bacteria that are missing in the viruses. Physicists of the Biotechnology Center of the TU Dresden (BIOTEC) were examining in cooperation with scientists from the University of Bristol, how the defense enzymes scan the bacteria DNA for these markers and how they communicate between them in order to start the defense mechanism. They were able to observe for the first time in real-time how the defense enzymes move by means of thermic energy very efficiently between two markers that are located far apart in the genome. The results of this study were published in the magazine Science.