Now, computational chemists at the University of Georgia have discovered for the first time that when a proton is knocked off one of the pairs of bases that make up DNA, a chain of damage begins that causes "lesions" in the DNA. These lesions, when replicated in the copying mechanisms of DNA, can lead to serious disorders such as cancer.
The research, just published in the Proceedings of the National Academy of Sciences (PNAS), was led by doctoral student Maria Lind and Henry F. Schaefer III, Graham-Perdue Professor of Chemistry. Other authors on the paper are doctoral student Partha Bera, postdoctoral associate Nancy Richardson and recent doctoral graduate Steven Wheeler.
Call it a "pinball proton." While chemists have shown other causes of DNA damage, the report in PNAS is the first to report how protons, knocked away by such mechanisms as radiation or chemical exposure, can cause lesions in DNA. The work was done entirely on computers in the Center for Computational Chemistry, part of the Franklin College of Arts and Sciences at UGA.
"This kind of damage in DNA subunits is about as basic as you can get," said Schaefer. "This is the simplest kind of lesion possible for such a system."
The double-helix structure of DNA has been known for more than half a century. This basic building block of life can "unzip" itself to create copies, a process at the heart of cell replication and growth. DNA is made of four "bases," Adenine, Guanine, Thymine and Cytosine, and each one pairs with its opposite to form bonds where the "information" of life is stored. Thus, Guanine pairs with Cytosine, and Thymine with Adenine.
The team at the University of Georgia studied how the removal of a proton from the Guanine-Cytosine (G-C) base pair is involved in creating lesions that can lead to replication errors. This pair has 10 protons, meaning there are numerous targets for processes that knock the protons off.
The lesions are breaks in the hydrogen bonds, of which there are two in the G-C base pair. (The Adenine-Thymine pair has three hydrogen bonds.)
"Our real goal is to examine all possible lesions in DNA subunits," said Lind.
The team discovered that the base pair minus its knocked-off proton can either break entirely or change its bonding angle--something that also causes improper replication.
"The C-G subunit is usually totally planar [flat]," said Lind. "If it twists, it could simply pull apart."
Though it has already been suspected that lesions in DNA caused by both high- and low-energy electrons result in cancer cell formation, the new study is the first evidence that protons do the same thing.
The study in PNAS also has other implications. Researchers are beginning to understand how DNA can be used as "molecular wire" in constructing electrical circuits. Such a breakthrough would allow small electronic devices to shrink even further, but how the electrical properties of DNA would work in such a context is not yet understood. The UGA research adds important knowledge about how so-called "deprotonated" DNA base pairs work and could be important in creating "DNA wire."
Kim Carlyle | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy