Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cholera protein structure – a target for vaccines & antibiotics – described by TSRI scientists

23.05.2003


A group of researchers from The Scripps Research Institute (TSRI) has solved structures of a bacterial protein called pilin, which is required for infection by pathogens that cause human diseases like meningitis, gonorrhea, diarrheal diseases, pneumonia, and cholera.

In the latest issue of the journal Molecular Cell, the TSRI group reports two key structures of these pilins and discoveries about their assembly into fibrous "pili." Because a whole class of bacterial pathogens require the assembly of pilin into the hair-like pilus filaments on their surface in order for them to move around, attach to, and infect host cells, the authors believe that this research provides essential knowledge to help scientists develop novel antibiotics and vaccines against these deadly and emerging bacterial diseases.

This work directly focuses on two such pathogens--Pseudomonas aeruginosa, which causes severe lung infections in cystic fibrosis patients, AIDS patients, and other immunocompromised individuals, and Vibrio cholerae, which causes cholera, a potentially fatal diarrheal disease that primarily afflicts people in developing countries.



"Cholera," says TSRI Professor John Tainer, Ph.D., "is a disease that could use better vaccines."

Tainer, who is an investigator in TSRI’s Department of Molecular Biology and a member of The Skaggs Institute for Chemical Biology at TSRI, determined the atomic structure of the pilus filaments with TSRI Senior Research Associate Lisa Craig, Ph.D., and three other key researchers--TSRI Professor Mark Yeager, computational expert and director of graphics development at TSRI Michael Pique, and Dartmouth Medical School Professor Ronald Taylor.

"If we can understand their atomic structure, we can go after developing vaccines that are highly specific," says Craig, who is first author on the paper.

The Structure and How It Was Solved

The pili are used by several types of bacteria to crawl around and stick to the intestine, lung, and other mucosal surfaces, and to pick up foreign genes and DNA, bringing them aboard to potentially increase the bacteria’s pathogenicity. In cholera, these pili are essential for the infection because they allow the bacteria to clump together and form a colony that protects them from the human immune response. This makes pili a good target for vaccine design, since blocking them should block the bacterium’s ability to cause infection.

However, solving the structure of these proteins has not been easy because of their size and shape. The pili themselves are assembled from thousands of copies of a single pilin subunit protein stacked together to resemble a microscopic thread--they are several hundred times longer than they are wide.

These structures are too large and flexible to be solved with the traditional techniques of structural biology used to study small proteins. So in the current study, the TSRI team was creative and combined more than one approach.

The group first solved the structure of the individual pilin proteins from the V. cholerae bacterium using x-ray crystallography--a technique where scientists first make crystals of molecules like proteins or DNA and then expose them to x-rays. The pattern of diffracted x-rays can then be collected and analyzed to determine the structure of the molecules in the crystal. Although a fragment of the V. cholerae pilin protein was missing in their structure, they were able to infer this structure by solving a full length structure of a pilin subunit from P. aeruginosa, which is important in infections of children with cystic fibrosis.

Craig, Yeager and Tainer then used a technique called electron microscopy to understand how the pilin proteins were organized in the pilus filaments. Electron microscopy uses a beam of electrons to magnify protein assemblies and other tiny structures up to one hundred thousand times onto a digital camera or a photographic plate.

The integration of x-ray crystallography and electron microscopy allowed Craig, Pique, and Tainer to build a model of the pili otherwise impossible at that level of molecular detail. The structures gave new insights into how the pili assemble and how they contribute to the pathogenesis of the bacteria--as well as providing a unique molecular map of these proteins that should aid in the design of new vaccines and therapeutics.

The research article, "Type IV Pilin Structure and Assembly: X-ray and EM Analyses of Vibrio cholerae Toxin Coregulated Pilus and Pseudomonas aeruginosa PAK Pilin" is authored by Lisa Craig, Ronald Taylor, Michael Pique, Brian Adair, Andrew Arvai, Mona Singh, Jane Lloyd, David Shin, Elizabeth Getzoff, Mark Yeager, Katrina Forest, and John Tainer and appears in the May 23, 2003 issue of the journal Molecular Cell.

The research was funded by the National Institutes of Health, The Skaggs Institute for Research, and the Canadian Institutes of Health Research.

More on Cholera: A Deadly Disease of Developing Nations

Although cholera was once common in this country, modern water treatment has virtually eliminated the disease domestically, though it is still a concern for U.S. world travelers. In the developing world and in areas with poor sewage treatment, cholera is still a major public health problem, and these areas frequently support outbreaks of disease. Cholera can be a deadly problem for children in third world countries. Epidemic outbreaks in the past have involved changes to the pilin protein, now structurally characterized by Scripps researchers.

Cholera is caused by an acute intestinal infection with the bacterium Vibrio cholerae. This usually occurs after someone has eaten food or drank water contaminated with the pathogen.

Cholera infections are sometimes mild, but result in watery diarrhea, vomiting, and severe fluid loss about five percent of the time. These cases are life-threatening and deadly where treatment through simple rehydration with a sugar and salt mixture is not available.

There is currently no effective vaccine available for this disease. According to the Centers for Disease Control and Prevention, the only cholera vaccine licensed in the United States has been discontinued because it offers only brief and incomplete immunity. For more information, please see:

Jason Bardi | EurekAlert!
Further information:
http://www.cdc.gov/ncidod/dbmd/diseaseinfo/cholera_g.htm.
http://www.scripps.edu/

More articles from Life Sciences:

nachricht New mechanisms uncovered explaining frost tolerance in plants
26.09.2016 | Technische Universität München

nachricht Chains of nanogold – forged with atomic precision
23.09.2016 | Suomen Akatemia (Academy of Finland)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

Im Focus: Launch of New Industry Working Group for Process Control in Laser Material Processing

At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.

In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...

Im Focus: New laser joining technologies at ‘K 2016’ trade fair

Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.

K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

ICPE in Graz for the seventh time

20.09.2016 | Event News

Using mathematical models to understand our brain

16.09.2016 | Event News

 
Latest News

Stronger turbine blades with molybdenum silicides

26.09.2016 | Materials Sciences

Scientists Find Twisting 3-D Raceway for Electrons in Nanoscale Crystal Slices

26.09.2016 | Materials Sciences

Lowering the Heat Makes New Materials Possible While Saving Energy

26.09.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>