Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Membranes in tight corners

10.07.2013
Photosynthesis takes place in specialized membrane systems, made up of stacked disks linked together by unstacked planar leaflets. An LMU team has now identified a protein that tucks the membrane in at the edge of each stack.

By making use of sunlight to generate molecular oxygen and other energy-rich chemical compounds that other organisms can utilize as nutrients, photosynthesis provides the basis for almost all life on Earth.


Scanning electron microscopy (SEM) micrograph of a chloroplast in maize (Zea mays) showing thylakoids (green) and assimilation starch granules (grey). (Prepared by freeze fracturing; micrograph is pseudo-colored.) (Source: G. Wanner LMU)

Radiant energy from the Sun is captured by pigment-protein complexes embedded in specialized membrane systems called thylakoids. The thylakoids of green plants reside within organelles called chloroplasts, membrane-bounded compartments in the cell cytoplasm that serve as self-contained reaction vessels.

Thylakoids are made of stacks of 5 to 20 flat membrane sacs called grana, and extended planar membrane sheets that serve to interconnect them, so that all thylakoids in a chloroplast form a continuous network. To form the stacks of appressed sacs, the membrane must be bent into a tight fold at their edges. This implies that the thylakoid membranes forming the grana stacks must somehow be induced to curve at regular intervals. “The origin of the stacked organization of the thylakoids and the local alterations in membrane curvature has been a complete mystery up to now,” says LMU biologist Professor Dario Leister.

Leaning into the curve with CURT1

Leister and his group have now identified a new family of proteins, whose members spontaneously cause membranes to bend. The researchers call them CURT1 proteins (for CURvature of Thylakoids). “Without CURT1 proteins, there are no stacks,” Leister reports. Using the model plant Arabidopsis, he and his colleagues have been able to show that the concentration of CURT is directly correlated with the number of thylakoid stacks in chloroplasts. CURT1 itself is primarily localized at the edges of the grana, exactly where the membrane is maximally curved. In addition, the researchers have shown in the test-tube that isolated CURT1 molecules spontaneously assemble into larger complexes that can alter the curvature of membranes. “It is therefore likely that the aggregation of several CURT1 molecules plays an important role in the formation of thylakoid stacks in the chloroplasts,” Leister concludes.

In the longer term, the new findings could contribute to the optimization of photosynthesis. The grana stacks in the thylakoids are enriched for the antennal proteins that gather and channel light energy and the reaction centers known as Photosystem II. They are therefore, in many respects, more efficient energy converters than the single-layered membrane sheets that connect them together, which harbor Photosystem I. Understanding how CURT1 functions might therefore allow one to increase the degree of stacking and enhance the efficiency of photosynthesis – and perhaps increase yields from crop plants. In cooperation with the Edmund Mach Foundation (Trento, Italy) and the University of Trento, the authors of the new study have applied for patent protection for the use of CURT1 in this setting.

The study was carried out in the context of Collaborative Research Center SFB-TR 1 (Endosymbiosis: From Prokaryotes to Eukaryotic Organelles), and was financed by the DFG.

Luise Dirscherl | EurekAlert!
Further information:
http://www.lmu.de

Further reports about: CURT1 LMU Membranes Photosystem crop plant protein complex

More articles from Life Sciences:

nachricht What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

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,...

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

Simple processing technique could cut cost of organic PV and wearable electronics

06.12.2016 | Materials Sciences

3-D printed kidney phantoms aid nuclear medicine dosing calibration

06.12.2016 | Medical Engineering

Robot on demand: Mobile machining of aircraft components with high precision

06.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>