Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The sweet science: Viruses switch grip to gain upper hand

15.09.2006
Carbohydrates can be attractive, especially when they come packaged in candy bars or never-ending bowls of pasta.

Even viruses - those bits of occasionally harmful genetic material enclosed in shells of protein and fat - crave carbs. Except viruses aren't seeking a taste treat. They want to latch onto the carbohydrates that protrude from the surface of our cells and mount an invasion.

By changing which carbohydrates they attach to, viruses are able to infect cells more efficiently - a finding that may prove valuable to scientists seeking ways to fight cancer or brain diseases, say University of Florida researchers writing in the current Journal of Biological Chemistry. The discovery also helps explain how flu and other viruses are able to stay a step ahead of the body's own versatile immune system.

"If you think about the flu virus, a few simple amino acid changes can be the difference between a virus your body can defend against and one that will make you sick," said Mavis Agbandje-McKenna, Ph.D., an associate professor of biochemistry and molecular biology in the UF College of Medicine and senior author of the paper. "It seems structural juxtapositions of amino acids play a role in determining how viruses recognize cells and whether the viruses are harmful."

... more about:
»MVMp »amino »amino acid »carbohydrates »glycan

The idea that proteins on a virus' outer shell mutate to get a more lethal grip on a cell's sugary coat of carbohydrates, or glycans, became apparent when UF scientists studied the Minute Virus of Mice, or MVM.

One strain of the virus, MVMp, is harmless and causes no ill effects, even in mice without a functioning immune system. However, a different version of the virus, MVMi, can be fatal to these mice. Both viruses resemble miniature, 20-sided soccer balls, and between them their outer protein shells differ by only 14 out of more than 500 amino acids.

But a few years ago, the normally mild MVMp virus mutated slightly, suddenly becoming harmful to the defenseless mice.

"One or two changes in amino acids made the difference between a virus that kills and one that does not kill mice," said Agbandje-McKenna, who is associated with both UF's McKnight Brain Institute and the UF Genetic Institute. "We wanted to know how such a slight change could make this virus become lethal."

Working with the Consortium for Functional Glycomics, an international team of more than 230 scientists under the National Institute of General Medical Sciences, UF researchers became the first to use a new technique called a glycan array to study how a whole, intact virus interacts with carbohydrates.

Scientists exposed 189 glycans mounted on a 3-by- 5-inch plastic plate to dangerous MVMi, harmless MVMp and three potentially dangerous, mutant strains of MVMp.

Scientists found MVMp proteins stuck to the same three glycans on the plate. However, one of the mutant MVMp viruses also bound to an additional glycan - one associated with the more dangerous MVMi strain.

"A single amino-acid change in the virus' protein shell changes how it can grip the cell, making it more deadly," she said. "Actually, the affinity is reduced, so the more deadly strain of the virus does not bind as tightly. We're not sure why, but it may be because it can more easily let go and get into the cell to cause disease. It's not giving the body the time to mount an immune response."

Understanding how viruses adapt to different hosts and different tissues could be useful for developing gene therapies, which involve introducing specially engineered genes into a patient's cells via apparently harmless viruses. In cancer treatment, the new genes might be intended to prompt the body's natural defenses, or actually attack the cancer cells themselves.

In terms of medical treatments, the finding helps explain why a virus would be able to home in on a cancer or brain cell - by recognizing sugars on the cell's surface, according to Hyun-Joo Nam, Ph.D., an assistant scientist in department of biochemistry and molecular biology and the paper's first author.

"Scientists want to use viruses they know to be nonpathogenic as vehicles for either gene and cancer therapies, and they also want to know how viruses target cancer and other differentiated cells," said Peter Tattersall, Ph.D., a professor of laboratory medicine and genetics at Yale University who was not involved in the research. "The most likely medical significance of this finding is for fine tuning viruses and vectors to target cancer and other differentiated cell types. This is a major field that is advancing rapidly."

John D. Pastor | EurekAlert!
Further information:
http://www.vpha.health.ufl.edu

Further reports about: MVMp amino amino acid carbohydrates glycan

More articles from Life Sciences:

nachricht Show me your leaves - Health check for urban trees
12.12.2017 | Gesellschaft für Ökologie e.V.

nachricht Liver Cancer: Lipid Synthesis Promotes Tumor Formation
12.12.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

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

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Long-lived storage of a photonic qubit for worldwide teleportation

12.12.2017 | Physics and Astronomy

Multi-year submarine-canyon study challenges textbook theories about turbidity currents

12.12.2017 | Earth Sciences

Electromagnetic water cloak eliminates drag and wake

12.12.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>