Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Brown Scientists Map Structure of DNA-Doctoring Protein Complex

08.12.2006
Mobile DNA, which inserts foreign genes into target cells, is a powerful force in the march of evolution and the spread of disease. Working with the lambda virus and E. coli bacteria, Brown University biologists have solved the structure of a six-protein complex critical to performing this gene-grafting surgery. The technique they developed could be used to reveal the structure of other critical protein complexes, landing the work on the cover of Molecular Cell.

More than half of the human genome is made up of bits of mobile DNA, which can travel inside the body and insert genes into the chromosomes of target cells. This DNA doctoring not only shapes species over time, it also spreads antibiotic resistance and is used by bacteria that spread Lyme disease and by viruses linked to certain forms of cancer.

Last year in Nature, scientists working in the Brown University lab of Arthur Landy and the Harvard Medical School lab of Thomas Ellenberger announced they had solved the structure of ë-integrase (ë-Int), the protein “surgeon” that allows mobile DNA to cut into a chromosome, insert its own genes, and then sew the chromosome back up. That work was conducted using the lambda virus, which infects Escherichia coli (E. coli) bacteria and serves as a model that scientists use to understand mobile DNA.

Now scientists in the Landy lab have solved the structure of a DNA-protein complex that acts as a team of “nurses,” aiding ë-Int during this snip-and-solder procedure known as site-specific recombination. The structure is a three-dimensional representation of the DNA within this complex. Pictured on the cover of the Nov. 17, 2006, journal Molecular Cell, it looks like DNA dressed for a party, a double helix decked with clumps of curly, colorful ribbon. By solving this structure, scientists now know how these six proteins interact with each other and fold DNA during site-specific recombination.

... more about:
»Cell »DNA »Landy »structure

“Once you know how these proteins and DNA are arranged, you have a much better sense of their function,” said Xingmin Sun, a postdoctoral research associate in the Landy lab and the lead author of the journal article. “And once you know their function, you begin to see how the real work inside cells gets done.”

Sun said solving the structure of the DNA-protein complex called for some creativity. Because it is a string of six proteins, the complex is too big and too flexible to analyze through standard methods such as X-ray crystallography.

Sun used fluorescence resonance energy transfer or FRET, a technique typically used to study small protein complexes in a solution. This time, Sun used FRET to study large protein complexes in a gel. He tagged the DNA with fluorescent dyes and purified the proteins, placing them in a gel that was then shot through with light. Sun measured the wavelengths of light as they bounced between the molecules of dye. Those measurements were then fed into a special software program created by Dale Mierke, a Brown professor of medical science, which plotted their positions to create the structural map.

“The real breakthrough here is successfully using FRET to determine the structure of a large protein-DNA complex,” Sun said. “Biologists now have a new tool to help them understand a variety of these complexes, including ones that control cell division, gene expression and DNA replication. So this technique represents a big advance.”

Former Brown postdoctoral research associates Marta Radman-Livaja and Sang Yeol Lee were part of the research team, along with Tapan Biswas, a former postdoctoral research associate at Harvard Medical School. Landy, a professor of medical science in Brown’s Department of Molecular Biology, Cell Biology and Biochemistry, acted as senior scientist on the project.

The National Institute of General Medical Sciences supported the work.

Editors: Brown University has a fiber link television studio available for domestic and international live and taped interviews and maintains an ISDN line for radio interviews. For more information, call the Office of Media Relations at (401) 863-2476.

Wendy Lawton | EurekAlert!
Further information:
http://www.brown.edu

Further reports about: Cell DNA Landy structure

More articles from Life Sciences:

nachricht Individual Receptors Caught at Work
19.10.2017 | Julius-Maximilians-Universität Würzburg

nachricht Rapid environmental change makes species more vulnerable to extinction
19.10.2017 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Rapid environmental change makes species more vulnerable to extinction

19.10.2017 | Life Sciences

Integrated lab-on-a-chip uses smartphone to quickly detect multiple pathogens

19.10.2017 | Interdisciplinary Research

Fossil coral reefs show sea level rose in bursts during last warming

19.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>