Featured Research

from universities, journals, and other organizations

Protective Shield Used By Hundreds Of Viruses Deciphered

Date:
February 17, 2009
Source:
Rice University
Summary:
A new image reveals the precise structure of the protective protein coat, or "capsid," shared by hundreds of known viruses. The image reveals the precise location of some 5 million atoms in a spherical type of capsid that many viruses use to shield their genomes.

High-energy X-ray diffraction was used to pinpoint some 5 million atoms in the protective protein coat used by hundreds of viruses.
Credit: J. Pan & Y.J. Tao/Rice University

 If a picture is worth a thousand words, then Rice University's precise new image of a virus' protective coat is seriously undervalued. More than three years in the making, the image contains some 5 million atoms -- each in precisely the right place -- and it could help scientists find better ways to both fight viral infections and design new gene therapies.

The stunning image, which appears online this week in the Proceedings of the National Academy of Sciences, reveals the structure of a type of protein coat shared by hundreds of known viruses containing double-stranded RNA genomes. The image was painstakingly created from hundreds of high-energy X-ray diffraction images and paints the clearest picture yet of the viruses' genome-encasing shell called a "capsid."

"When these viruses invade cells, the capsids get taken inside and never completely break apart," said lead researcher Jane Tao, assistant professor of biochemistry and cell biology at Rice.

Capsids come into play because viruses can reproduce themselves only by invading a host cell and highjacking its biochemical machinery. But when they invade, viruses need to seal off their genetic payload to prevent it from being destroyed by the cell's protective mechanisms.

Though there are more than 5,000 known viruses, including whole families that are marked by wide variations in genetic payload and other characteristics, most of them use either a helical or a spherical capsid.

In their attempt to map precisely the spherical variety, Tao and lead author Junhua Pan, a postdoctoral fellow at Rice, first had to create a crystalline form of the capsid that could be X-rayed. They chose the oft-studied Penicillium stoloniferum virus F, or PsV-F, a virus that infects the fungus that makes penicillin. PsV-F uses the spherical capsid; although it does not infect humans, it is similar to a rotavirus and others that do.

"Spherical viruses like this have symmetry like a soccer ball or geodesic dome," Pan said. "The whole capsid contains exactly 120 copies of a single protein."

Previous studies had shown that spherical capsids contain dozens of copies of the capsid protein, or CP, in an interlocking arrangement. The new research identified the sphere's basic building block, a four-piece arrangement of CP molecules called a tetramer, which could also be building blocks for other viruses' protein coats. By deciphering both the arrangement and the basic building block, the research team hopes to learn more about the capsid-forming process.

"Because many viruses use this type of capsid, understanding how it forms could lead to new approaches for antiviral therapies," Tao said. "It could also aid researchers who are trying to create designer viruses and other tools that can deliver therapeutic genes into cells."

The research team used X-ray crystallography to decipher the structure of the capsid. Pan first spent several months creating hundreds of crystal samples of PsV-F. He then collected hundreds of high-intensity, high-energy X-ray diffraction images at the Cornell High Energy Synchotron Source, or CHESS, in Ithaca, N.Y. By analyzing the way the X-rays scattered when they struck the crystals, Pan and the team created a precise three-dimensional image of the spherical capsid.

The research team included Rice postdoctoral researcher Li Lin and former graduate student Liping Dong; Max Nibert of Harvard Medical School; Timothy Baker, Wendy Ochoa and Robert Sinkovits, all of the University of California, San Diego; and Said Ghabrial and Wendy Havens, both of the University of Kentucky.

The research was supported by the National Institutes of Health, the USDA, the Welch Foundation, the Kresge Science Initiative Endowment Fund, the Agouron Foundation and the San Diego Supercomputer Center.


Story Source:

The above story is based on materials provided by Rice University. Note: Materials may be edited for content and length.


Cite This Page:

Rice University. "Protective Shield Used By Hundreds Of Viruses Deciphered." ScienceDaily. ScienceDaily, 17 February 2009. <www.sciencedaily.com/releases/2009/02/090216175205.htm>.
Rice University. (2009, February 17). Protective Shield Used By Hundreds Of Viruses Deciphered. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2009/02/090216175205.htm
Rice University. "Protective Shield Used By Hundreds Of Viruses Deciphered." ScienceDaily. www.sciencedaily.com/releases/2009/02/090216175205.htm (accessed September 17, 2014).

Share This



More Plants & Animals News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) — The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) — Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) — Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

AFP (Sep. 16, 2014) — Since the arrival of Ebola in Ivory Coast, Ivorians have been abandoning their pets, particularly monkeys, in the fear that they may transmit the virus. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

      Technology News



      Save/Print:
      Share:  

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile iPhone Android Web
      Follow Facebook Twitter Google+
      Subscribe RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins