- Two DNA double helices have been visualised locking together, the first time this fundamental biological process has been captured
- Using high-powered atomic force microscopy, researchers from the University of Sheffield and the University of York have solved a decade-old mystery on how DNA molecules overcome their identical negative charges to pair up
- Advanced computer simulations revealed that positively charged metal ions act as tiny molecular bridges, nestling inside the grooves to lock the two strands together
- This discovery could help researchers identify regions of the genome specially involved in DNA pairing, which may become particularly important when mutations disrupt normal cellular processes and contribute to cancer
Researchers have captured the moment two DNA molecules zip together, overcoming their identical negative charges to pair up, solving a mechanism that has puzzled scientists for more than 20 years.
Using high-powered atomic force microscopy, scientists at the University of Sheffield and the University of York directly imaged two DNA double helices locking together, the first time this fundamental biological process has been visualised.
Like charges normally repel one another, yet DNA molecules must pair up inside living cells to carry out essential biological processes. This pairing plays a crucial role in genetic recombination, gene silencing, chromosome packaging and the development of cancer.
The researchers observed short DNA fragments matching up with exact precision, groove for groove. Advanced computer simulations revealed that positively charged metal ions, including nickel, magnesium and calcium, act as tiny molecular bridges, nestling inside the grooves to lock the two strands together.
Dr. Thomas Catley, co-lead author from the School of Chemical Materials and Biological Engineering at the University of Sheffield, said: "To be able to directly visualise this long-hypothesised mechanism for the first time was incredible. The advanced imaging techniques at our disposal have allowed us to uncover these key DNA interactions which have implications in many key cellular processes. It opens the door to studying other DNA interactions that, until now, have only existed as theory.
"Hopefully, these programmable interactions could eventually help engineers design custom DNA structures for future biotechnology, such as DNA origami and shed light on how DNA is actually packaged inside cells."
Professor Agnes Noy, from the School of Physics, Engineering and Technology at the University of York who co-led the research, said: "This discovery could help researchers identify regions of the genome specially involved in DNA pairing. These regions may become particularly important when mutations disrupt normal cellular processes and contribute to cancer."
