Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Novel optical tweezers instrument unravels bacterial DNA

VU Amsterdam researchers have developed an optical tweezers instrument, which they used to unravel bacterial chromosomes. The researchers, headed by Dr. Gijs Wuite, have demonstrated how an important protein, called H-NS, bridges DNA strands in bacteria.

Thanks to this technology, it has now been proven that the seemingly chaotic cluster of bacterial DNA is in fact organized and can function dynamically. Moreover, the H-NS protein is a potential target for developing medication to treat bacterial infections. The research findings will be published in the scientific journal Nature on November 16, 2006.

Unlike cells in the human body, bacteria do not have a nucleus. These micro-organisms are much less complex than our human body cells, but this, rather surprisingly, makes it more difficult to determine how the DNA in a bacterial cell is organized. Prior to the use of the newly developed optical tweezers instrument, it was very difficult to study the spatial organization of bacterial DNA.

In human and animal cells, DNA-strands are coiled up inside chromosomes and extremely well organized. The bacterial chromosome is much more dynamically organized by a small group of proteins that non-specifically bind the DNA. Consequently, these proteins have more, and more general, functions. The DNA appears to be unorganized, like a ball of noodles in the cell – or so it seemed at least.

For cell division or DNA repair, the bacterium must duplicate its DNA, and this cannot be done without choreographed order. DNA duplication is the result of (among other factors) the action of DNA binding motor proteins: they slide along the DNA and replicate every nucleotide in the DNA-sequence. It was already known that certain proteins prevented the DNA from becoming entangled; but what was unknown is how it was then possible for a motor protein to slide along the DNA-strands. This mystery has now been solved.

Gijs Wuite, Remus Dame and Maarten Noom, the authors of the article to be published in Nature, began by demonstrating that a specific protein (namely, histone-like nucleoid structuring protein, H-NS) bridges two DNA strands. H-NS is a small protein that has on both its ends a small, ball-like element that can attach to DNA, probably fitting in the small cavities along the DNA’s spiral staircase-like structure. Remus Dame: “It’s great that in our measurements the helical shape of the DNA emerges. But what is much more important is that we were able to measure the strength with which the H-NS is bound to the DNA.” It is a weak bond: each H-NS arm is loosely bound to a DNA-helix.

Moreover this bond is unstable: over a certain period of time, the arm of the H-NS comes loose, in order to then reattach itself to the DNA. Because there is a lot of H-NS protein between the two parallel DNA-helices, the overall bridging activity is unhindered if each protein occasionally let’s go and then reattaches itself. Gijs Wuite: “And this precisely explains why motor proteins are unhindered by H-NS when they move along the DNA: the force these proteins exert is greater, and H-NS simply allows them to pass. This has never before been demonstrated.”

Department Science Communication | alfa
Further information:

More articles from Physics and Astronomy:

nachricht Novel light sources made of 2D materials
28.10.2016 | Julius-Maximilians-Universität Würzburg

nachricht OU-led team discovers rare, newborn tri-star system using ALMA
27.10.2016 | University of Oklahoma

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Steering a fusion plasma toward stability

28.10.2016 | Power and Electrical Engineering

Bioluminescent sensor causes brain cells to glow in the dark

28.10.2016 | Life Sciences

Activation of 2 genes linked to development of atherosclerosis

28.10.2016 | Life Sciences

More VideoLinks >>>