Solving an old problem with DNA

Print edition : January 25, 2013

The normal (right-handed helical, or B-form) DNA will switch to left-handed DNA, or Z-form, when it is physically twisted or when a lot of salt is added to the solution. Researchers at the University of Luxembourg were able to accurately calculate for the first time the amount of salt that is required to do this.

It has been known since the 1970s that excessive salt causes DNA to reverse its twist, but the complexity of the DNA molecule makes a theoretical explanation that can correctly predict the amount of salt to do this difficult. DNA in the Z-form is treated by natural repair enzymes and is therefore usually deleted from the cell. Z-DNA in a cell leads to loss of function and cancer. Josh Berryman and Tanja Schilling of the University of Luxembourg have found a method of calculation that predicts the transition with unprecedented accuracy. With this success, the team is optimistic that it will be able to perform similar mathematical analyses for a variety of other substances. “It will enable us to predict material properties such as melting temperatures or elasticity. And this will be done with high accuracy using our new technique. Hence, we can now design new materials and biomaterials on the computer more effectively than before,” said Tanja Schilling.