Electronic structure of single DNA molecules revealed -genetic mutations implica

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Electronic structure of single DNA molecules revealed

http://www.news-medical.net/?id=35750

Utilizing a technique that combines low temperature measurements and

theoretical calculations, Hebrew University of Jerusalem scientists

and others have revealed for the first time the electronic structure

of single DNA molecules.

The knowledge of the electronic properties of DNA is an important

issue in many scientific areas from biochemistry to nanotechnology --

for example in the study of DNA damage by ultraviolet radiation that

may cause the generation of free radicals and genetic mutations. In

those cases, DNA repair occurs spontaneously via an electronic charge

transfer along the DNA helix that restores the damaged molecular

bonds.

In nano-bioelectronics, which is the advanced research field devoted

to the study of biological molecules (to produce electrical

nanocircuits, for example), it has been suggested that DNA, or its

derivatives, may become used as possible conducting molecular wires

in the realization of molecular computing networks which are smaller

and more efficient than those produced today with silicon technology.

The knowledge that has been acquired in this project, say the

researchers, may also be relevant for current attempts to develop new

sophisticated, reliable, faster and cheaper ways to decode the

sequence of human DNA.

The research, published in the prestigious journal Nature Materials,

is a result of an international collaboration. The research was

conducted by Errez Shapir and coordinated by Dr. Danny Porath at the

Department of Physical Chemistry and Center for Nanoscience and

Nanotechnology at the Hebrew University and by Dr. Di Felice at

the S3 Center of INFM-CNR in Modena, Italy. Also collaborating in the

project were Prof. Kotlyar at Tel Aviv University, who

synthesized the molecules, the CINECA supercomputing center in Italy,

and Prof. Gianaurelio Cuniberti at the University of Regensburg,

Germany.

In their work, the researchers were able to decode the electronic

structure of DNA and to understand how the electrons distribute into

the various parts of the double helix, a result that has been pursued

by scientists for many years, but was previously hindered by

technical problems.

The success of this project was finally achieved thanks to

collaboration between experimental and theoretical scientists who

worked with long and homogeneous DNA molecules at minus 195 degrees

Celsius, using a scanning tunneling microscope (STM) to measure the

current that passes across a molecule deposited on a gold substrate.

Then, by means of theoretical calculations based on the solution of

quantum equations, the electronic structure of DNA corresponding to

the measured current has been obtained. These results also suggest an

identification of the parts of the double helix that contribute to

the charge flow along the molecule.

http://www.huji.ac.il/