It has long been known that UV light can damage DNA, reducing its ability to replicate and interact with proteins, and often resulting in the development of skin cancers. However, not much is known about how the elasticity of DNA strands is altered upon exposure to UV light. Now a group of researchers at Duke University have developed a method to measure changes in the mechanical properties of DNA upon irradiation with UV light.
Piotr Marszalek and his colleagues have conducted single-molecule force spectroscopy measurements on viral DNA, which show the unraveling of the DNA double helix upon exposure to UV irradiation. The researchers essentially pick up individual DNA molecules with the tip of a scanning probe microscope and stretch it while measuring the forces generated. These “stretch—release” measurements enable the accurate determination of changes in the elasticity of the DNA strands. Upon exposure to UV light, the force profile of the viral DNA changes dramatically in a dose-dependent manner. The force curve of intact DNA is characterized by a plateau region. This characteristic plateau is drastically reduced in width with increasing exposure to UV light.
UV light induces the crosslinking of the constituent DNA bases within the polynucleotide chains, as well as causes the formation of lesions by linking together the adjacent strands. The small changes in structure induced by this crosslinking can very profoundly affect the ability of DNA to recognize specific molecules, and can thus completely disrupt its ability to replicate and interact with the transcriptional machinery to synthesize proteins. Marszalek and his colleagues have also examined synthetic DNA to figure out the extent to which different bases are affected by UV light. They conclude that the changes in the force profile of viral DNA exposed to UV light are due to the local unwinding of the double helix in some regions arising from the massive formation of crosslinked structures.
“These are the first measurements that establish a relationship between DNA nanomechanics and damage”, said Marszalek. He believes that this work paves the way for using stretch—release force spectroscopy measurements in DNA diagnostics.
Author: Piotr E. Marszalek, Duke University (USA), http://www.mems.duke.edu/faculty/marszalek/index.php
Title: Nanomechanical Fingerprints of UV Damage To DNA
Small 2007, 3, No. 5, 809–813, doi: 10.1002/smll.200600592
About Small: Micro and Nano: No small Matter. Science at the nano- and microscale is currently receiving enormous wordwide interest. Published by Wiley-VCH, Small provides the very best forum for experimental and theoretical studies of fundamental and applied interdisciplinary research at these dimensions. Read an attractive mix of peer-reviewed Communications, Reviews, Concepts, Highlights, Essays, and Full Papers.
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy