DNA radiation damage: insights from ab initio molecular dynamics simulations
DIPC Seminars
- Speaker
-
Jorge Kohanoff. Queen's University Belfast, United Kingdom.
- When
-
2016/07/27
14:00 - Place
- Donostia International Physics Center
- Add to calendar
- iCal
Learning how ionising radiation interacts with DNA at the molecular level is
important to assess the risks posed by various radiation sources, e.g. UV,
X-rays, or ions, and to improve radiotherapeutic treatments of cancer.
Radiation can interact directly with DNA, or indirectly by ionising the
surrounding medium, thus generating a large number of electrons and leaving
behind as many radicals. Both, electrons and radicals can interact with DNA.
For a long time the responsibility for DNA damage was ascribed to attack by
radicals. In 2000, a seminal work by L. Sanche's group in Sherbrooke (Canada)
showed that electrons can also cause damage to DNA by a mechanism named
dissociative electron attachment. The electron is captured in a resonant
electronic state forming a transient negative ion, that decays by transferring
electronic energy to vibrations of specific bonds that can eventually break.
If these correspond to DNA strand breaks, they constitute the first step
towards unrecoverable damage and cell death.
In this seminar I will present our efforts in trying to understand the role of
low-energy (excess) electrons at the molecular level by means of computer
simulation of DNA fragments solvated in water and in the presence of amino
acids. We are particularly interested in assessing the role of the fluctuating
environment, as most of the existing calculations and experiments are carried
out under rather artificial conditions, like gas phase molecules or clusters,
or frozen samples, but rarely under the conditions prevalent in the cell. I
will also present some preliminary results of the interaction between radio-
and chemotherapy in DNA intercalated with Cisplatin.