Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Virus known for its photo ops makes its movie screen debut

23.08.2004


High-resolution snapshots of a virus attacking its host – which have culminated in a movie of the process – could reveal secrets of viral infection and improve gene therapy techniques, according to a Purdue University research group.


artist’s conception of the T4 virus


T4 virus



Structural biologists including Michael G. Rossmann have obtained clearer pictures of how the T4 virus, long known to infect E. coli bacteria, alters its shape as it prepares to pierce its host’s cell membrane. The complicated infection process requires a flower-like section of the virus, known as the baseplate, to shape-shift by dramatically changing the configuration of the numerous proteins that form it. The team has taken cryoelectron microscope images of the baseplate from different moments in the process and transformed them into a brief animated movie, helping scientists understand how infection occurs and possibly enabling them to apply this knowledge for the benefit of human patients in the future.

"Instead of a still photo of the baseplate, we now have a movie of it opening," said Rossmann, who is Henley Distinguished Professor of Biological Sciences in Purdue’s School of Science. "A better understanding of the infection process is a step forward for fundamental science, but it also could allow scientists to alter the baseplate so that the virus could infect cells other than E. coli. T4 might then be used to deliver beneficial genes to damaged or infected human tissue."


The research was performed at Purdue and the Institute of Bioorganic Chemistry in Moscow by a team of scientists including first author Petr G. Leiman, Paul R. Chipman, Victor A. Kostyuchenko, Vadim V. Mesyanzhinov and Rossmann. The paper appears in the current (Aug. 20) issue of the scientific journal Cell, and it builds on research the team published last year regarding the baseplate of the T4 virus. This previous paper offered a close-up picture of the baseplate at a single moment in time, information that was valuable because of the detail it provided of the part of the virus that attached itself to E. coli’s surface.

"It was good to see the baseplate at such unprecedented resolution, but the infection process is not a still picture – it’s a story," Rossmann said. "We knew we needed to see more than one scene in that story if we were ever to understand its full meaning."

The baseplate is composed of 16 types of protein molecules, most present in multiple copies. Before infection, these proteins fit together to form a hexagonal shape. Together with the 12 legs that extend from the T4’s tail to grasp the victim E. coli, the virus resembles an Apollo moon lander. When the T4 approaches "touchdown" on an E. coli’s cell membrane, the baseplate’s proteins unfold in a complex motion, opening like a flower’s petals and changing shape from a hexagon to a star.

"We can now visualize how these proteins move together, which means a great deal for anyone trying to comprehend infection," Rossmann said. "If you saw a car speed past you for the first time ever, it might impress you, but you probably wouldn’t have much of an idea how it works. But if you stop it, you can examine the engine and find out. That’s essentially what we’ve done – stop the virus at two points in its attack on E. coli and examine the difference."

Scientists speculate that viruses are a key player in the evolutionary process on planet Earth. Far from being mere purveyors of disease, the viral infection process also could be partly responsible for spreading new genes among organisms rapidly and preparing their hosts for future environmental changes. This is part of viruses’ fascination for scientists like those on Rossmann’s team and why some medical professionals seek to use altered viruses to cure illnesses rather than cause them.

"Viruses’ great talent – injecting genetic material into living cells – could make them valuable for delivering healthy DNA to cells damaged by injury or cancer," said Leiman, a postdoctoral researcher in Rossmann’s lab. "T4’s baseplate proteins could be altered so it could infect human cells instead of E. coli. This study could bring us one step closer to using it as a gene therapy vehicle."

Gene therapy using T4 remains a distant possibility, however, and Rossmann said the true value of the team’s latest research was for the fundamental understanding it provides of the viral world.

"Viruses are among the tiniest of biological entities, yet nature has designed them to perform very complicated tasks," he said. "Understanding their behavior will open doors for scientists in many disciplines, especially with biologists, chemists and physicists increasingly working side by side."

As a step in that direction, Rossmann said he hopes that he and his colleagues will be able to obtain a better picture of the components within the tiny mechanism that is the baseplate.

"Our knowledge of the orientation of the proteins within the baseplate could still stand some improvement," he said. "We’d like to look under the hood of this car, so to speak, and determine precisely how the carburetor sits on the engine. Determining the structure and interactions of these proteins will help us down that road."

The research was funded in part by grants from the National Science Foundation, the International Human Frontier Science Program and the Howard Hughes Medical Institute.

Rossmann’s team is associated with Purdue’s Markey Center for Structural Biology, which consists of laboratories that use a combination of cryoelectron microscopy, crystallography, and molecular biology to elucidate the processes of viral entry, replication and pathogenesis.

Michael Rossmann | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

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...

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

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>