A single photon sensitivity digital camera used with total internal reflection microscopy (TIRFM) enabled researchers to prove EcoRV enzymes can jump as well as slide along strands of DNA.
It is hoped this discovery will shed light on how damaged sections of DNA are detected and repaired by the body's scavenger enzymes and lead to a better understanding of certain genetic disorders.
The researchers, led by Dr Pierre Desbiolles at the Laboratoire Kastler Brossel, CRNS and Universite Pierre et Marie Curie, developed a system based on an Andor Technology iXon860 EMCCD capable of detecting single photons originating from fluorescent Cy3 molecules bound to individual enzyme molecules.
This detection level was required as each EcoRV enzyme was only tagged with one of two Cy3 labels and imaging had to be undertaken dynamically.
By acquiring extended time series of individual DNA binding events, the team could confirm an earlier suggestion that EcoRV could slide along a DNA strand to access nearby areas.
However, it was unclear whether EcoRV could also jump along DNA between fragments spaced further apart.
The researchers used a direct microscopic observation technique to obtain clear images that confirmed long-distance excursions of enzyme on DNA were possible.
