Navigation Links
Keep your distance! Why cells and organelles don't get stuck
Date:8/30/2012

Biomembranes enclose biological cells like a skin. They also surround organelles that carry out important functions in metabolism and cell division. Scientists have long known in principle how biomembranes are built up, and also that water molecules play a role in maintaining the optimal distance between neighboring membranesotherwise they could not fulfill their vital functions. Now, with the help of computer simulations, scientists of the Technische Universitt Mnchen (TUM) and the Freie Universitt Berlin have discovered two different mechanisms that prevent neighboring membrane surfaces from sticking together. Their results appear in the Proceedings of the National Academy of Sciences.

Biomembranes consist of lipids, chain-like fat molecules stacked side by side. In the aqueous environment of cells, the lipids organize themselves into a so-called bilayer with fat-soluble "hydrophobic" ends of the molecular chains facing inward and water-soluble "hydrophilic" ends facing outward. If the water-soluble surfaces of two membranes come too close to each other, a pressure is generatedhydration repulsionthat prevents the membrane surfaces from touching. Between two intact biomembranes there is always a film of water just a few nanometers thick. Until now, however, it was unclear how hydration repulsion works on the molecular level.

By means of complex simulations, the scientists discovered two different mechanisms whose contribution depends on the distance between the membranes. If the membranes are separated by around one nanometer or more, the water molecules play the decisive role in holding them apart. Since they have to orient themselves simultaneously to the lipids of both membrane surfaces, they give up their preferred spatial arrangement. Then they function like "bumpers," pushing the membranes apart. When the separation is smaller, the lipids in the opposing membrane surfaces mutually inhibit their own mobility, and the repulsive force is increased.

For some time, these two mechanisms had been discussed as possible explanations for hydration repulsion. Now, with their computer simulations, the scientists from TUM and FU Berlin have for the first time correctly predicted the strength of the pressure, that is, in agreement with experimental results. In doing so, they have elucidated in detail the significance of the different mechanisms. "We were able to predict the water pressure so accurately because we determined the chemical potential of the water precisely in our computations," explains Dr. Emanuel Schneck, formerly a member of the work group of FU Berlin Professor Roland Netz (then at TUM). Schneck is currently a researcher at the Institute Laue Langevin (ILL). "The chemical potential indicates how 'willing' the water molecules are to stay in a particular spot. In order for us to obtain correct results, the potential at the membrane surfaces and the potential in the surrounding water must have the same value in our simulations."

The researchers now want to translate their results to many more biological surfaces and, in the process, initiate considerably more complex computer models.


'/>"/>
Contact: Patrick Regan
regan@zv.tum.de
49-089-289-10515
Technische Universitaet Muenchen
Source:Eurekalert  

Related biology news :

1. Tortoise and the hare: New drug stops rushing cancer cells, slow and steady healthy cells unharmed
2. Stem cells can repair a damaged cornea
3. Scientists produce eye structures from human blood-derived stem cells
4. Study demonstrates cells can acquire new functions through transcriptional regulatory network
5. Epigenetic signatures direct the repair potential of reprogrammed cells
6. Researchers print live cells with a standard inkjet printer
7. Nanopills release drugs directly from the inside of cells
8. Protein jailbreak helps breast cancer cells live
9. Newly found protein helps cells build tissues
10. BU researchers derive purified lung and thyroid progenitors from embryonic stem cells
11. Housekeeping mechanism for brain stem cells discovered
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Keep your distance! Why cells and organelles don't get stuck
(Date:2/27/2017)... --  Strategic Cyber Ventures , the industry,s first cybersecurity ... million investment in  Polarity , the first commercial human ... based and is led by cybersecurity veterans Tom ... Gula , also a longtime cybersecurity veteran and founder ... A round of funding. This new funding will be ...
(Date:2/21/2017)... Der weltweite Biobanking-Sektor wird bis ... Gespräch mit mehr als 50 Vertretern aus verschiedenen Branchen wurde ... um diese Prognose zu realisieren. ... Zu den Schwierigkeiten ... Mittel für die Biobank, die Implementierung Zeit sparender Technologien, ...
(Date:2/10/2017)... Research and Markets has announced the addition of ... Commercial Aspects" to their offering. ... Biomarkers play an important ... selection of treatment as well for monitoring the results. There ... modern medicine. Biochip/microarray technologies and next generation sequencing are also ...
Breaking Biology News(10 mins):
(Date:3/23/2017)... 23, 2017  GlobeImmune, Inc. today announced it has ... of 12,835,490 shares of its common stock to NantCell, ... connection with the sale of its common stock, NantCell ... issue to GlobeImmune 200,000 shares, an estimated $2.0 million ... "We are pleased to enter into this strategic agreement ...
(Date:3/23/2017)... March 23, 2017 NetworkNewsWire Editorial Coverage  ... Cancer ... significant strain on health care systems, in terms of costs ... so too does the development of innovative and efficient therapies ... Among the many types of cancer treatments, a growing number ...
(Date:3/23/2017)... ... March 23, 2017 , ... Advanced Polymer Monitoring Technologies ... Dr. Sigmund “Sig” Floyd as Vice President ? Global Business Development. Dr. Floyd ... , “Dr. Floyd’s career has spanned 30 years in the chemicals and equipment ...
(Date:3/22/2017)... 2017  UBM and the Massachusetts Medical Device ... partnership and the third annual Massachusetts Medtech Week. Massachusetts ... st Annual MassMEDIC Conference held in conjunction ... 2017. MassMEDIC will feature a ... and CEO, Scott Whitaker , at its ...
Breaking Biology Technology: