The structure of DNA is generally acknowledged to exist as a twofold helix, however extraordinary DNA structures likewise exist. According to a new study by the University of East Anglia, the shape of DNA can be changed with a range of triggers including copper and oxygen.
This system can be used as a switch – the DNA in the two different conditions has completely different shapes so we can recognize this as either ‘on’ or ‘off’. This has been used for DNA nano-machine applications.
Lead researcher Dr Zoe Waller from UEA’s School of Pharmacy said: “DNA is a genetic material, and its structure usually looks a bit like a twisted ladder – a double helix. But alternative DNA structures exist and are thought to potentially play a role in the development of genetic diseases, such as diabetes or cancer.”
“It was previously known that the structure of a piece of DNA could be changed using acid, which causes it to fold up into a shape called an ‘i-motif’.”
Scientists previously identified that the shape of DNA can also be changed into a second structure called a hairpin by using copper salts. This change would then be able to be switched utilizing EDTA (Ethylenediaminetetraacetic acid) – an operator generally found in shampoo and other household items. This extended the capacity of DNA into two switches rather than one.
The discovery demonstrates that different triggers, including oxygen and a substance like Vitamin C, can likewise trigger DNA to change its shape.
During an experiment, scientists added copper salts to DNA in oxygen-free conditions. This changes its shapes into i-motif. When exposing the i-motif to oxygen in the air, it then changed from in i-motif into a hairpin. The DNA can regain its original shape i-motif by adding sodium ascorbate, which is similar to vitamin C, and back to an unfolded state using a chelating agent.
Dr Waller said, “This research means that now we can not only change the shape of DNA using a change in pH, we can use copper salts and oxygen to have the same effect.”
“There are many applications that this research could be used for. The potential changes in shape can be used as on/off switches for logic gates in DNA computing. Our findings could also be used in nanotechnology, or to change the properties of materials such as gels.”
The study is published in the journal Nucleic Acids Research on Friday, May 25, 2018.