Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists Discover DNA Knot Keeps Viral Genes Tightly Corked Inside Shell

19.06.2008
A novel twist of DNA may keep viral genes tightly wound within a capsule, waiting for ejection into a host, a high-resolution analysis of its structure has revealed.

Using electron microscopy and three-dimensional computer reconstruction, UC San Diego biologists and chemists have produced the most detailed image yet of the protein envelope of an asymmetrical virus and the viral DNA packed within, they report this week in the journal Structure. The image, with a resolution of less than a nanometer, or a millionth of a millimeter, will help to unravel how the virus locks onto its host and infects the cells by injecting its DNA.

By assembling more than 12,000 microscopic views of frozen viral particles from different angles, UCSD chemists Jinghua Tang, Norman Olson and Timothy Baker, a professor of chemistry and biological sciences, have determined the structure of a bacteriophage called phi29 with a resolution finer than 8 Angstroms (one Angstrom equals a tenth of a nanometer). Their project was part of a long-term collaboration with molecular virologist Dwight Anderson and his colleagues at the University of Minnesota.

Although the structures of spherical viruses with a high degree of symmetry have been resolved using similar methods, many more images were required to accomplish the same task for the head-and-tail shape of phi29. The UCSD scientists said their images of phi29 are twice as fine as those created in previous efforts to visualize viruses with a similar shape.

... more about:
»DNA »structure

A comparison between images of the virus with and without its DNA cargo revealed that the DNA twists tightly into a donut shape, or toroid, in the neck of the virus between its head and tail. “This highly distorted DNA structure is unlike anything previously seen or even predicted in a virus,” said Timothy Baker who headed the research team. “It’s an improbably tight turn for DNA, which is generally considered inflexible over very small distances.”

During assembly of the virus, a molecular motor in the neck winds the DNA strand into a tight coil within the head. “It’s under tremendous pressure -- about 20 times that of champagne in a bottle,” said Tang, the lead author of the paper.

The knot-like shape of the toroid, along with interlocking bumps in the protein envelope, may keep the DNA wedged into the capsid until the virus docks onto the host cell.

"It's poised in this tube waiting to go through the bacterial wall," Baker said. "All of the components work together to create an infection machine."

Susan Brown | EurekAlert!
Further information:
http://www.ucsd.edu

Further reports about: DNA structure

More articles from Life Sciences:

nachricht More genes are active in high-performance maize
19.01.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht How plants see light
19.01.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

More genes are active in high-performance maize

19.01.2018 | Life Sciences

How plants see light

19.01.2018 | Life Sciences

Artificial agent designs quantum experiments

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>