Highest resolution images of DNA reveal that it is surprisingly wavy – tech2.org

Highest resolution images of DNA reveal that it is surprisingly wavy


Gif: ALB Payne et al., 2021 / Nature Communications

Scientists have captured the highest resolution images of DNA ever taken, revealing twisting and twisting behaviors never seen before.

Deoxyribonucleic acid, also known as DNA, can be surprisingly active when crammed and contorted inside a cell, according to a new research published in Nature Communications. These hidden movements were revealed by computer simulations powered by the highest resolution images ever taken of a single DNA molecule. The new study is exposing behaviors never before seen in the self-replicating molecule, and this research could eventually lead to the development of powerful new gene therapies.

“Seeing is believing, but with something as small as DNA, seeing the helical structure of the entire DNA molecule was extremely challenging,” said Alice Pyne, the first author of the paper and a materials scientist at the University of Sheffield, in a release. of the University. “The videos we have developed allow us to observe DNA twisting in a level of detail never seen before.”

Atomic force microscopy image of a DNA molecule.

Atomic force microscopy image of a DNA molecule.
Picture: ALB Payne et al., 2021 / Nature Communications

Scientists have previously he used microscopes to look at the DNA and its twisted ladder configuration, but these were limited to static views of the molecule. What scientists haven’t been able to see is how the intense winding of DNA affects its double helix structure. To achieve this, Pyne and his colleagues combined high-resolution atomic force microscopy (AFM) with computer simulations of molecular dynamics, which revealed the kinks.

Long, highly organized strands of DNA are crammed inside our cells. As the new study shows, this results in some surprisingly dynamic physical behaviors.

Atomic force microscopy image of a DNA minicircle.

Atomic force microscopy image of a DNA minicircle.
Picture: ALB Payne et al., 2021 / Nature Comm

Agnes Noy, a professor at the University of York and a co-author of the study, said the microscopic images and computer simulations matched so well that they increased the resolution of their experiments, allowing the team to “track how each atom of the dance double helix DNA “.

For the study, the researchers analyzed minicircles of DNA, in which a small strand joins at both ends, forming a loop structure. DNA minicircles have been described before and are believed to be important health indicators.

Microscopic images of the DNA minicircles in their “relaxed” position (ie, no twists) revealed very little movement, but additional twists brought the loop to life, resulting in more vigorous movements. These dynamic movements can serve an important purpose, helping DNA find binding partners and facilitating growth.

The new atomic force microscopy shows, “in remarkable detail,” how “wrinkled, bubbled, twisted, denatured, and oddly shaped” are actually minicircles of DNA, “which we hope to be able to control one day,” said the Baylor biologist. College of Medicine. Lynn Zechiedrich, who provided the minicircles for the study, said in the statement from the University of Sheffield.

In fact, more information about DNA, and how it can become so compact, could lead to the development of entirely new medical interventions, including improved DNA-based diagnostics and therapies, according to the researchers.

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