Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Protein engineering produces ’molecular switch’

28.03.2003


In this Johns Hopkins engineering lab, Gurkan Guntas and Marc Ostermeier used a technique called domain insertion to join two proteins and create a molecular ’switch.’
Photo by Will Kirk


Technique could lead to new drug delivery systems, biological warfare sensors

Using a lab technique called domain insertion, Johns Hopkins researchers have joined two proteins in a way that creates a molecular “switch.” The result, the researchers say, is a microscopic protein partnership in which one member controls the activity of the other. Similarly coupled proteins may someday be used to produce specialized molecules that deliver lethal drugs only to cancerous cells. They also might be used to set off a warning signal when biological warfare agents are present.

The technique used to produce this molecular switch was reported March 27 in New Orleans at the 225th national meeting of the American Chemical Society,



“We’ve taken two proteins that normally have nothing to do with one another, spliced them together genetically and created a fusion protein in which the two components now ‘talk’ to one another,” said Marc Ostermeier, assistant professor in the Department of Chemical and Biomolecular Engineering at Johns Hopkins. “More important, we’ve shown that one of these partners is able to modulate or control the activity of the other. This could lead to very exciting practical applications in medical treatment and bio-sensing.”

To prove the production of a molecular switch is possible, Ostermeier, assisted by doctoral student Gurkan Guntas, started with two proteins that typically do not interact: beta-lactamase and the maltose binding protein found in a harmless form of E. coli bacteria. Each protein has a distinct activity that makes it easy to monitor. Beta-lactamase is an enzyme that can disable and degrade penicillin-like antibiotics. Maltose binding protein binds to a type of sugar called maltose that the E. coli cells can use as food.

Using a technique called domain insertion, the Johns Hopkins researchers placed beta-lactamase genes inside genes for maltose binding protein. To do this, they snipped the maltose binding genes, using enzymes that act like molecular scissors to cut the genes as though they were tiny strips of paper. A second enzyme was used to re-attach these severed strips to each side of a beta-lactamase gene, producing a single gene strip measuring approximately the combined length of the original pieces. This random cut-and-paste process took place within a test tube and created hundreds of thousands of combined genes. Because the pieces were cut and reassembled at different locations along the maltose binding gene, the combined genes produced new proteins with different characteristics.

Ostermeier believed a very small number of these new fusion proteins might possess the molecular switch behavior he was looking for. To find them, he and Guntas took a cue from the process of evolution, or “survival of the fittest.” By looking for the E. coli that thrived in maltose, they could isolate only the ones in which the maltose binding partner was still active (in other words, it still bound itself to maltose). By then mixing them with an antibiotic, the researchers could find the ones in which the beta-lactamase remained active and capable of reacting against the antibiotic. Through such survival tests, the researchers ultimately were able to find two fusion proteins in which not only were both proteins still active, but in which the presence of maltose actually caused the beta-lactamase partner to step up its attack on an antibiotic.

“In other words,” Ostermeier said, “one part of this coupled protein sent a signal, telling the other part to change its behavior. This is the first clear demonstration that you can apply the domain insertion technique to control the activity of an enzyme. If we can replicate this with other proteins, we can create biological agents that don’t exist in nature but can be very useful in important applications.”

For example, Ostermeier said, one part of a fusion protein might react only to cancer cells, signaling its partner to release a toxin to kill the diseased tissue. Healthy cells, however, would not set off the switch and would thus be left unharmed. Ostermeier also suggested that one part of a fusion protein might react to the presence of a biological warfare agent, signaling its partner to set off a bright green flourescent glow that could alert soldiers and others to the danger.

The Johns Hopkins University has applied for U.S. and international patents related to Ostermeier’s molecular switch technology and the techniques used to produce them. Ostermeier’s research has been funded by grants from the American Cancer Society and the Maryland Cigarette Restitution Fund.

Phil Sneiderman | EurekAlert!
Further information:
http://www.jhu.edu/
http://www.jhu.edu/news_info/news/home03/mar03/molecule.html
http://www.jhu.edu/chbe/index.asp

More articles from Life Sciences:

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

nachricht CWRU researchers find a chemical solution to shrink digital data storage
22.06.2017 | Case Western Reserve University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A new technique isolates neuronal activity during memory consolidation

22.06.2017 | Life Sciences

Plant inspiration could lead to flexible electronics

22.06.2017 | Materials Sciences

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>