The first crystal structure of an alternative DNA shape from the insulin gene has been revealed by a UCL-led research team. DNA is widely accepted to be formed of two strands that wind around one another, known as a double helix, but it is possible for DNA to change shape and structure. The new study, published in Nature Communications , reveals the detail in the structure of a type of DNA called i-motif by crystallising it for the first time.
Co-lead author Dr. Zoë Waller (UCL School of Pharmacy) said: "DNA is our genetic material, and its structure usually looks a bit like a twisted ladder called a double helix. This shape is iconic, but alternative DNA structures exist and are thought to potentially play a role in the development of genetic diseases, such as diabetes or cancer.
" The researchers were focusing on i-motif DNA, which has an interlocking structure resembling a knot, and was only confirmed to be found in living human cells in 2018. It was previously known that there was a region of DNA in the insulin gene that can fold into alternative DNA structures and shapes. It was also known that this region of DNA varies between people.
Our work shows that these different variants in sequence fold into different DNA shapes." Dr. Zoë Waller, UCL School of Pharmacy The scientists employed a crystallography technique that concentrates a solution containing the DNA, enabling crystals to form, which is an important method for researchers to see the structure of DNA using X-.