Feb. 28, 2013 ? A novel discovery brings a close to a 17-year-old scientific debate about the impact of mechanical stretching on the structure of DNA.
A team of researchers led by Associate Professor Yan Jie from the Department of Physics at the National University of Singapore (NUS) Faculty of Science has identified three new distinct overstretched deoxyribonucleic acid (DNA) structures caused by mechanical stretching. This discovery provides a clear answer to a long-running debate among scientists over the nature of DNA overstretching.
Debate on Possible DNA Structural Transitions
Recent single-molecule studies revealed that mechanical stretching could induce transitions to elongated DNA structures. Three possible elongated DNA structures have been proposed, namely: a single-stranded DNA under tension, DNA bubbles consisting two parallel, separated single-stranded DNA under tension, and a new form of base-paired double-stranded DNA. The existence of the three transitions has been heavily discussed among scientists for some 17 years.
To fully understand the nature of DNA overstretching, the team led by Assoc Prof Yan, which comprises members from NUS, the University of Minnesota and the Massachusetts Institute of Technology, explored the possible structural transitions.
Three Distinct Transitions Revealed
In their recent study, the researchers systematically investigated the three possible transitions induced by mechanical stretching, with methods to control DNA construct, temperature, force and salt concentration. Their data successfully identified all the three proposed structures and fully characterised their respective thermo-mechanical properties. These findings were first published on the online version of the Proceedings of the National Academy of Sciences on 19 February 2013. These findings complete the picture about the structures of DNA under tension, providing a conclusion to the 17-year-old debate.
Biological Implications and Potential Applications
As forces over a wide range are present in the DNA of cells, the researchers' findings provide new perspectives of possible force-dependent regulations of critical biological processes, such as DNA damage repair and gene transcriptions.
In addition, as many recently developed DNA devices are based on thermo-mechanical properties of various DNA structural motifs, these findings may also have potential applications in designing new DNA devices for the future.
The Next Step
To further their research, Assoc Prof Yan and his team will study the physiological functions of the three overstretched DNA structures, and investigate the presence of any new DNA structures under other mechanical constraints.
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Davidson Farmer?s Market is back again Saturday for the first of three winter tailgate markets during March, including an extra market added at the month?s end. Meanwhile, the dining calendar is busy in March, with wine dinners, beer tastings and live music at Ass Clown Brewery, a Russian food and music festival at Davidson College, and a big two-day St. Patrick?s Day celebration at Galway Hooker. Read on for the details.![[ Back to EurekAlert! ]](http://www.eurekalert.org/images/back2e.gif){kind=small}
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A bill to create an athletic commission in South Dakota is going nowhere fast, largely thanks to the ignorance of Gov. Dennis Daugaard and state house Rep. Steve Hickey.
The simple fact is that a random NFL player is at far greater risk of a serious brain injury than is a random MMA fighter. Sadly, neither Gov. Daugaard nor Rep. Hickey bothered to do much investigation or educate themselves before speaking out.
A fear of many states with strong commissions is that promoters will travel across state lines to put on shows in states such as South Dakota, where there is no regulation and where, as a result, costs are less. But the result is that it is far less safe for the competitors.
