Navigation Links
Scientists discover DNA knot keeps viral genes tightly corked inside shell
Date:6/17/2008

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.

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."


'/>"/>

Contact: Susan Brown
mailro:sdbrown@ucsd.edu
858-246-0161
University of California - San Diego
Source:Eurekalert  

Related biology news :

1. Scientists find potential protein biomarkers for growth hormone
2. Scientists confirm that parts of earliest genetic material may have come from the stars
3. Scientists find 245 million-year-old burrows of land vertebrates in Antarctica
4. Brain stem cells can be awakened, say Schepens scientists
5. Scientists demonstrate feasibility of preventing malaria parasite from becoming sexually mature
6. New fingerprint breakthrough by forensic scientists
7. Young mineral scientists rock!
8. Scientists discover stinging truths about jellyfish blooms in the Bering Sea
9. Scientists find bacteria thriving on a feast of seafloor rock
10. Leiden scientists sequence first female DNA
11. Scientists announce top 10 new species, issue SOS
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Scientists discover DNA knot keeps viral genes tightly corked inside shell
(Date:6/2/2016)... June 2, 2016 Perimeter Surveillance ... Unmanned Systems, Physical Infrastructure, Support & Other Service  ... visiongain offers comprehensive analysis of the global ... will generate revenues of $17.98 billion in 2016. ... Inc, a leader in software and hardware technologies for ...
(Date:5/24/2016)... IRVINE, Calif. , May 24, 2016 Ampronix facilitates superior patient care ... LMD3251MT  3D medical LCD display is the latest premium product recently added to ... ... ... Sony 3d Imaging- LCD Medical Display- Ampronix News ...
(Date:5/16/2016)... May 16, 2016   EyeLock LLC , a ... the opening of an IoT Center of Excellence in ... expand the development of embedded iris biometric applications. ... of convenience and security with unmatched biometric accuracy, making ... aside from DNA. EyeLock,s platform uses video technology to ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... ... innovative medical technologies, services and solutions to the healthcare market. The company's primary ... various distribution, manufacturing, sales and marketing strategies that are necessary to help companies ...
(Date:6/24/2016)... June 24, 2016  Regular discussions on a range of ... between the two entities said Poloz. Speaking at ... Ottawa , he pointed to the country,s inflation target, ... government. "In certain ... institutions have common economic goals, why not sit down and ...
(Date:6/23/2016)... ... June 23, 2016 , ... Mosio, a ... eBook, “Clinical Trials Patient Recruitment and Retention Tips.” Partnering with experienced clinical research ... by providing practical tips, tools, and strategies for clinical researchers. , “The landscape ...
(Date:6/23/2016)... June 23, 2016 A person commits a crime, ... scene to track the criminal down. An outbreak ... and Drug Administration (FDA) uses DNA evidence to track down ... Sound far-fetched? It,s not. The FDA has increasingly used ... investigations of foodborne illnesses. Put as simply as possible, whole ...
Breaking Biology Technology: