Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Putting light-harvesters on the spot: how photosynthetic proteins get into the membrane

19.10.2011
RUB biologists publish new model for protein transport in plant cells / Journal of Biological Chemistry: how photosynthetic proteins get into the membrane

How the light-harvesting complexes required for photosynthesis get to their site of action in the plant cell is reported by RUB biologists in the Journal of Biological Chemistry. The team led by Prof. Dr. Danja Schünemann (RUB working group on the molecular biology of plant organelles) has demonstrated for the first time that a membrane protein interacts with a single soluble protein to anchor the subunits of the light-harvesting complexes in the membrane. The researchers propose a new model that explains the integration into the membrane through the formation of a pore.


New transport model: Proteins of the light-harvesting complexes (green) have to be installed in special membranes inside the chloroplasts (thylakoid membranes). Soluble proteins (43, 54) transport them there. The membrane protein Alb3 forms a pore through interaction with one of the soluble proteins (43), through which the light-harvesting complex proteins are inserted into the membrane (Figure published in the Journal of Biological Chemistry) Figure: The American Society for Biochemistry and Molecular Biology

Light harvesting

Photosynthesis occurs in special areas of the plant cells, the chloroplasts, whereby the energy-converting process takes place in specific protein complexes (photosystems). To capture the light energy and efficiently transmit it to the photosystems, light-harvesting complexes are required which work like antenna. “The proteins of the light-harvesting complexes are the most abundant membrane proteins on Earth” says Dr. Beatrix Dünschede of the RUB. “There is a special transport mechanism that conveys them into the chloroplasts and incorporates them into the photosynthetic membrane”. Exactly how the various transport proteins interact with each other had, up to now, been unclear.

Interaction between only two proteins

Several soluble proteins and the membrane protein Alb3 that channels the proteins of the light-harvesting complexes into the membrane are involved in the transport. Bochum’s biologists examined intact, isolated plant cells and found that, for this purpose, Alb3 interacts with only a single soluble transport protein (cpSRP43). They confirmed this result in a second experiment with artificial membrane systems. “In a further experiment, we identified the region in Alb3 to which the soluble protein cpSRP43 binds” explains the RUB biologist Dr. Thomas Bals. “It turned out that the binding site is partly within the membrane and thus cannot be freely accessible for cpSRP43.”

Through the pore into the membrane

Schünemann’s team explains the data with a new model. The soluble transport proteins bind the proteins of the light-harvesting complexes and transport them to the membrane. There, the soluble transport protein cpSRP43 interacts with the membrane protein Alb3, which then forms a pore. The proteins of the light-harvesting complexes get into the pore, and from there they are released laterally into the membrane. “There are proteins in other organisms which are very similar to Alb3 and apparently also form pores” says Dünschede. “This supports our model. We are now planning new experiments in order to recreate the entire transport path in an artificial system.”

Bibliographic record

B. Dünschede, T. Bals, S. Funke, D. Schünemann (2011) Interaction studies between the chloroplast signal recognition particle subunit cpSRP43 and the full-length translocase Alb3 reveal a membrane-embedded binding region in Alb3, Journal of Biological Chemistry, 286, 35187-35195, doi: 10.1074/jbc.M111.250746

Further information

Working group on the molecular biology of plant organelles, Department for Biology and Biotechnology at the Ruhr-Universität, 44780 Bochum

Dr. Beatrix Dünschede, Tel. 0234/32-28467
beatrix.duenschede@rub.de
Dr. Thomas Bals, Tel. 0234/32-28467
thomas.bals@rub.de
Prof. Dr. Danja Schünemann, Tel: 0234/32-24293
danja.schuenemann@rub.de
Click for more
Homepage of the working group:
http://homepage.ruhr-uni-bochum.de/Danja.Schuenemann/Seiten_dt/index.html
Editor: Dr. Julia Weiler

Dr. Josef König | idw
Further information:
http://homepage.ruhr-uni-bochum.de/Danja.Schuenemann/Seiten_dt/index.html

More articles from Life Sciences:

nachricht A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich

nachricht New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>