In a recently published article, researchers achieved a new level of precision in measuring the energy differences between the two configurations of DNA molecules, the normal and the damaged configuration
A normal DNA helix will change its configuration from a right helix to a left helix when it is physically twisted or when a large amount of salt is added to the solution in which it is found. Researchers from the University of Luxembourg were able to accurately measure, for the first time ever, the amount of salt required for this. Its unusual and damaged left configuration in the body of DNA (Z-DNA) leads to disruptions in its activity in cells and even to cancer.
In a recently published article, researchers achieved a new level of precision in measuring the energy differences between the two configurations of DNA molecules, the normal and the damaged configuration.
Since the seventies, scientists have known that a large amount of salt causes DNA to change the direction of its configuration from a right helix to a left helix. A left-handed DNA helix (in the Z configuration) is treated by our normal repair enzymes as damaged material, so, in most cases, it will be removed from the cell. Removal of genetic material can lead to cancer and other diseases, so the transition from the normal configuration to the defective configuration (BZ) is not just a theoretical question. Despite this, in light of the complexity of the DNA molecule, a satisfactory theoretical explanation has never been given for the exact amount of salt that will cause this transition.
Two researchers from the University of Luxembourg, Dr. Josh Berryman and Professor Tanja Schilling, have now succeeded in finding a calculation method to predict this transition with an unprecedented level of accuracy. Following their success in describing the very complex molecules of DNA, the researchers believe that they will be able to conduct similar mathematical analyzes for a variety of other substances as well. "Our innovative method will make it possible to predict some of the properties of the material, for example its melting temperature or its elasticity, and this calculation will be carried out with a high level of accuracy while utilizing our new method. Therefore, we are now able to design new materials and biomaterials with our computer and method more efficiently than before," said the lead researcher. The news about the study
The full article about the study
The two different configurations of DNA - the normal form, B, and the damaged form, Z.
5 תגובות
The normal helical structure of DNA is obtained as a result of regular hydrogen bonds between the two chains. Salt breaks up in water into ions that compete for the polar parts of the chains and therefore break up the hydrogen bonds. In this situation, the hydrophilic sides of the molecule rotate outwards for maximum contact with the water and salt, and the hydrophobic regions tend to come together creating hydrophobic interactions (van der Waals) between themselves. In this whole process, there is no change in the covalent bonds, which means that the chirality of each chain is preserved (just as you can press your palms face to face or back to back and in both cases the right hand is right and the left hand is left regardless of their position in relation to each other).
Is there a connection to the consumption of salts in foods?
What is interesting here is what the found formula is, and if it really predicts what it claims to consistently predict.
If so, it is possible (for example) to find maximum strength as well as extreme points of other parameters, and this is a significant progress.
There's a difference. There are molecules in which the active substance works only when it is on one side of the chirality. And there is an extreme case - thalidomide, beneficial on one side, very harmful on the other.
As far as I know there is no chemical difference between two sides of chiral molecules so I did not understand how adding salt (chemical process) in a certain amount causes the side to change,
I would appreciate it if someone could explain to me what is the chemical process that occurs when salt is added?