Supercoiled DNA Twists and Transforms into Strange Shapes

First Posted: Oct 12, 2015 06:47 PM EDT

Scientists have created some new images of the three-dimensional structure of supercoiled DNA. The new images, which are the sharpest yet taken, reveal that the DNA's shape is much more dynamic than the well-known double helix.

Various DNA shapes, including figure-8s, were imaged using a powerful microcopy technique by researchers. This revealed the dynamic nature of DNA, which constantly morphs and shifts into different shapes rather than remaining static.

The double helix shape has a firm place in the public's collective consciousness. It's often touted as the only structure of DNA. However, the shape of DNA isn't always that simple.

"When Watson and Crick described the DNA double helix, they were looking at a tiny part of a real genome, only about one turn of the double helix," said Sarah Harris, one of the researchers, in a news release. "This is about 12 DNA 'base pairs,' which are the building blocks of DNA that form the rungs of the helical ladder. Our study looks at DNA on a somewhat grander scale-several hundreds of base pairs-and even this relatively modest increase in size reveals a whole new richness in the behavior of the DNA molecule."

The researchers created a test to make sure that the tiny twisted up DNA circles that they made in the lab acted in the same way as the full-length DNA strands within our cells. Then, they used an enzyme that manipulates the twist of DNA. The test revealed that the enzyme relieved the winding stress from all of the supercoiled circles, which is its normal job in the human body. This means that the DNA in the circles must look and act like the much longer DNA that the enzyme encounters in human cells.

The findings reveal a bit more about how DNA acts and looks. This, in turn, may help researchers develop future treatments.

The findings are published in the journal Nature Communications.

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TagsDNA, DNA Sequencing, 3d, Models, Model, Image, Images, Genetics