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 Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>