Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Novel optical tweezers instrument unravels bacterial DNA

17.11.2006
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:
http://www.nature.com/nature/journal/v444/n7117/index.html
http://www.vu.nl

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

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 silicon etching technique crafts 3-D gradient refractive index micro-optics

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...

Im Focus: Quantum Particles Form Droplets

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...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

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,...

Im Focus: Molecules change shape when wet

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...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

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

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>