How do the two DNA strands bind together? The secret in water

Mohammed Shaban

Scientists from Chalmers University of Technology in Sweden have refuted the prevailing theory that hydrogen bonds are what binds the two DNA strands together, making it clear that water is the key to that mystery - a fundamental discovery that opens the door to a new understanding of medical and life science research.

Genes carry our genetic codes on the DNA, so DNA is made up of biological polymers wrapped around each other, forming the characteristic double helix of the DNA molecule.

For decades, the hydrogen bonds between these polymers were thought to be the main reason that binds the double helix strips together in a parallel anti-parallel form, which was changed after a recent study in the journal Pinas late August.

Environment Key Puzzle
Researchers have shown that the surrounding environment is the secret of the spiral structure of the DNA strands. In an aquatic environment around the DNA strands, hydrophobic nitrogen bases - a component of DNA polymers - are trying to take cover.

So she pushes herself into the interior of the double strip, trying to create a water-repellent environment in which she can stay. Hydrogen bonds then begin to form between the corresponding nitrogenous bases in pairs in a correct sequence, such as oil repulsion from water, as the creation of an indoor water-repellent environment is the impetus for nitrogenous bases to come together to confront the surrounding aquatic environment.

The researchers used a water-repellent polyethylene glycol compound to gradually change the environment around the DNA molecule from water-loving to hydrophobic, in an attempt to find the limit at which the molecule changes. The researchers observed that at the boundary between the water-loving and hating environment, the characteristic spiral shape of the DNA molecule began to disintegrate.

The importance of discovery
This discovery is critical to understanding the relationship between DNA and its environment. "Cells always try to protect the DNA molecule and not expose it to hydrophobic environments, which may sometimes contain some harmful molecules," said Bobo Feng, one of the researchers in the study. You need to activate the DNA molecule to copy, read, or even fix it. It has to expose it to a water-repellent environment. "

For example, if DNA is doubled, pairs of nitrogenous bases have to dissociate from each other, enabling the double strip to open up a transcriptase enzyme that works on both sides of the helix to create a new DNA molecule.

Similarly, during DNA repair, the cells undergo a damaged part of the DNA in a hydrophobic environment to be replaced. There are catalytic proteins that create this hydrophobic environment, and we know that this type of protein is essential in all DNA repair processes, which of course means that the solution may be to combat many serious diseases.

Future prospects carried by the discovery
Understanding these proteins inspires many new ideas on how to fight strains of antibiotic-resistant bacteria, as well as in the treatment of cancer. We know that bacteria use RecA to repair their DNA. The researchers therefore believe that their findings may provide a fresh insight into understanding the process, and then stop it and kill the bacteria.

These repair proteins in human cells are known as Rad51, which repair DNA or otherwise develop cancer.

"To understand cancer, we need to understand how to repair DNA better. To understand that, we first have to understand the DNA molecule itself," Feng adds. "What we didn't understand before we researched, because we thought that hydrogen bonds are what complicates a strip. Now, we have shown that instead, it is the creation of a water-hating environment that lies behind it. ”

He explains that the DNA molecule behaves quite differently in the hydrophobic environment, which helps us to understand the DNA molecule and how to repair it. It is not surprising that no such thing has been discovered so far. The DNA molecule in a water-hating environment and studying its behavior in this environment. "