Improving tumour radiation therapy: When basic ions break DNA down

July 16, 2014

A new study relevant for cancer radiation therapy shows that DNA building blocks are susceptible to fragmentation on contact with the full range of ions from alkaline element species.

Scientists now have a better understanding of how short DNA strands decompose in microseconds. A European team found new pathways that occur universally when DNA strands are exposed to from a family of alkaline and alkaline earth elements. These ions tend to replace protons in the DNA backbone and at the same time induce a reactive conformation leading more readily to fragmentation. These findings by Andreas Piekarczyk, from the University of Iceland, and colleagues have been published in a study in European Physical Journal D. They could contribute to optimising cancerous tumour therapy through a greater understanding of how radiation and its by-products, reactive intermediate particles, interact with complex DNA structures.

In cancer radiation therapy, it is not the radiation itself that directly damages the DNA strands, or oligonucleotides. But rather, it is the secondary reactive particles, leading to the creation of charged intermediates. Here, the authors have studied one of these charged intermediates in the form of so-called protonated metastable DNA hexamers.

To do so, the authors created selected oligonucleotide-metal-ion complexes that they selected to have between zero and six metal ions. They then followed these complexes' fragmentation reactions using a technique called time-of-flight mass spectrometry. By comparing the different species, they could deduce how the underlying metal-ion-induced oligonucleotide fragmentation works.

They discovered that metal ion-induced fragmentation of oligonucleotides is universal with all alkaline and alkaline earth metal ions, for example, lithium, Li+; potassium, K+; rubidium, Rb+; magnesium, Mg2+ and calcium, Ca2+. They had previously reached the same conclusion for sodium ions—which are ubiquitous in nature, in the form of sodium chloride, or salt. Once the number of sodium ions per nucleotide is high enough, the study shows, it triggers an unexpected oligonucleotide fragmentation reaction.

Explore further: Exchange of bismuth atoms for chloride ions with retention of structure

More information: A. Piekarczyk, I. Bald, H. D. Flosadottir, B. Ómarsson, A. Lafosse, O. Ingolfssson (2014), Influence of metal ion complexation on the metastable fragmentation of DNA oligohexamers, European Physical Journal D DOI: 10.1140/epjd/e2014-40838-7.

Related Stories

Satisfying metals' thirst vital for high-capacity batteries

June 2, 2014

( —When a multiply charged aluminum or magnesium cation encounters a single water molecule, the result can be explosive. The metal ion rips an electron from the water molecule, causing a molecular-level explosion, ...

Recommended for you

A new form of real gold, almost as light as air

November 25, 2015

Researchers at ETH Zurich have created a new type of foam made of real gold. It is the lightest form ever produced of the precious metal: a thousand times lighter than its conventional form and yet it is nearly impossible ...

Moonlighting molecules: Finding new uses for old enzymes

November 27, 2015

A collaboration between the University of Cambridge and MedImmune, the global biologics research and development arm of AstraZeneca, has led researchers to identify a potentially significant new application for a well-known ...

Atom-sized craters make a catalyst much more active

November 24, 2015

Bombarding and stretching an important industrial catalyst opens up tiny holes on its surface where atoms can attach and react, greatly increasing its activity as a promoter of chemical reactions, according to a study by ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.