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
How molecules teeter in a laser field
18.01.2019 | Forschungsverbund Berlin
Discovery of enhanced bone growth could lead to new treatments for osteoporosis
18.01.2019 | University of California - Los Angeles
The scientific and political community alike stress the importance of German Antarctic research
Joint Press Release from the BMBF and AWI
The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...
World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles
The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:
The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.
One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
18.01.2019 | Materials Sciences
18.01.2019 | Life Sciences
18.01.2019 | Health and Medicine