Natural channel proteins are integrated into artificial membranes to facilitate the transport of ions and molecules. Researchers at the University of Basel have now been able to measure the movement of these channel proteins for the first time. They move up to ten times slower than in their natural environment, namely the cell membrane. As reported in academic journal “Nano Letters”, the results may prove useful to the ongoing development of new applications such as nanoreactors and artificial organelles.
The membranes of the cells in our bodies are only approximately 4 to 5 nanometers thick and consist of a complex mixture of lipids and specific membrane proteins, which also include channel proteins. This kind of cell membrane can be described as a fluid 2-D solution, in which the components are able to move laterally. These movements within the membrane are dependent on the flexibility and fluidity of the components and ultimately determine the functionality of the membrane.
Dynamic channel proteins
Chemists at the National Center of Competence in Research (NCCR) Molecular Systems Engineering working under Professor Wolfgang Meier and Professor Cornelia Palivan from the University of Basel have now integrated three different channel proteins into artificial membranes of 9 to 13 nanometers in thickness and have measured their movements for the first time.
The researchers began by creating large membrane models with embedded and dyed channel proteins; they then put them on a glass surface and measured them using a single-molecule measuring method known as fluorescence correlation spectroscopy. All three channel proteins were able to move freely within the membranes of various thicknesses – this took up to ten times longer than in the lipid bilayers of their natural environment.
Flexibility is a necessity
In thicker membranes, the building blocks of the membrane (polymers) must be able to condense around the channel proteins in order to alter their fixed size. To do so, the membrane building blocks have to be sufficiently flexible. This had already been described in theory.
The researchers at the University of Basel have now been able to measure this in a practical experiment for the first time, demonstrating that the thicker the membrane, the slower the movement of the channel protein is in comparison to the movement of the actual polymers that form the membrane.
“This phenomenon is effectively a local decrease in fluidity caused by condensation of the polymers,” explains lead author Fabian Itel. In essence, however, the behavior of the channel proteins in the artificial membranes is comparable to that in their natural environment, the lipid bilayer, with the time scale of the movements being approximately ten times lower. The research project received funding from the Swiss National Science Foundation and the NCCR Molecular Systems Engineering.
Fabian Itel, Adrian Najer, Cornelia G. Palivan, and Wolfgang Meier
Dynamics of membrane proteins within synthetic polymer membranes with large hydrophobic mismatch
Nano Letters (2015), doi: 10.1021/acs.nanolett.5b00699
Olivia Poisson | Universität Basel
Researchers identify how bacterium survives in oxygen-poor environments
22.11.2017 | Columbia University
Researchers discover specific tumor environment that triggers cells to metastasize
22.11.2017 | University of California - San Diego
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Medical Engineering
22.11.2017 | Materials Sciences
22.11.2017 | Health and Medicine