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 Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>