Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 


Snapshot reveals details about photosynthesis

Together with a large international research team, Johannes Messinger of Umeå University in Sweden has taken another step toward an understanding of photosynthesis and developing artificial photosynthesis.

With a combination of a x-ray free-electron laser and spectroscopy, the team has managed to see the electronic structure of a manganese complex, a chemical compound related to how photosynthesis splits water.

Caption: Ultra-short x-ray pulse striking molecules containing manganese. Illustration: Greg Stewart, National Accelerator Laboratory vid Stanford University

The experiments used the Linac Coherent Light Source (LCLS), which is a free-electron x-ray laser facility at Stanford University in the US. The wavelength of the laser is roughly the same as the breadth of an atom, and each pulse of light lasts 50 femtoseconds (10-15). This is an extremely short interval of time: there are more femtoseconds in one second than there are seconds in a person’s life. Such extremely short wavelengths and short light pulses constitute ideal conditions for imaging chemical reactions with atomic resolution at room temperature while the chemical reactions are ongoing.

The research group has previously used LCLS to perform structural analyses of isolated photosynthesis complexes from plants’ photosystem II at room temperature. Now the group has combined the method with spectroscopy and is the first team to succeed in seeing at LCLS the electronic structure of a manganese complex similar to that found in photosystem II. Manganese is a transitional metal that, together with calcium and oxygen, forms the water-splitting catalyst in photosystem II.

A very simple example of a spectrometer is a prism, which separates sunlight into all the colors of the rainbow. The spectrometer used in this study functions in a similar manner, but with a group of 16 specialized crystals that diffract the x-rays emitted from the sample in resonse of being excited by an x-ray pulse onto a detector array.

To the delight of the scientists, the manganese compounds remained intact long enough for them to observe detailed information about the electronic structure before the compounds were destroyed by the very intense X-ray laser beam.

“Having both structural information and spectroscopic information means that we can much better understand how the structural changes of the whole complex and the chemical changes on the active surface of the catalysts work together to enable the enzymes to perform complex chemical reactions at room temperature,” says Johannes Messinger, professor at the Department of Chemistry at Umeå University.

The chemical reaction the research group aims to understand is the splitting of water in photosystem II, as this understanding is also key for developing artificial photosynthesis– that is, for building devices for producing hydrogen from sunlight and water. To be able to exploit sunlight for producing fuels that can be stored and the used when needed would help solve the world’s ever-more acute energy problems.

The new research findings are being published in the highly regarded journal Proceedings of the National Academy of Sciences, PNAS.

Two major research projects at Umeå University are focusing on the development of artificial photosynthesis by imitating plants’ very successful way of exploiting solar energy. Both projects (“solar fuels” and “artificial leaf”) are directed by Johannes Messinger, professor at the Department of Chemistry at Umeå University.

Original publication:
Alonso-Mori Roberto, et. al: Energy-dispersive X-ray emission spectroscopy using an X-ray free-electron laser in a shot-by-shot mode. PNAS, November 5 2012, doi:10.1073/pnas.1211384109
For more information, please contact:
Johannes Messinger
Telephone: phone: +46 (0)90-786 59 33

Ingrid Söderbergh | idw
Further information:

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Hochpräzise Verschaltung in der Hirnrinde

Es ist noch immer weitgehend unbekannt, wie die komplexen neuronalen Netzwerke im Gehirn aufgebaut sind. Insbesondere in der Hirnrinde der Säugetiere, wo Sehen, Denken und Orientierung berechnet werden, sind die Regeln, nach denen die Nervenzellen miteinander verschaltet sind, nur unzureichend erforscht. Wissenschaftler um Moritz Helmstaedter vom Max-Planck-Institut für Hirnforschung in Frankfurt am Main und Helene Schmidt vom Bernstein-Zentrum der Humboldt-Universität in Berlin haben nun in dem Teil der Großhirnrinde, der für die räumliche Orientierung zuständig ist, ein überraschend präzises Verschaltungsmuster der Nervenzellen entdeckt.

Wie die Forscher in Nature berichten (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005), haben die...

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Wundermaterial Graphen: Gewölbt wie das Polster eines Chesterfield-Sofas

Graphen besitzt extreme Eigenschaften und ist vielseitig verwendbar. Mit einem Trick lassen sich sogar die Spins im Graphen kontrollieren. Dies gelang einem HZB-Team schon vor einiger Zeit: Die Physiker haben dafür eine Lage Graphen auf einem Nickelsubstrat aufgebracht und Goldatome dazwischen eingeschleust. Im Fachblatt 2D Materials zeigen sie nun, warum dies sich derartig stark auf die Spins auswirkt. Graphen kommt so auch als Material für künftige Informationstechnologien infrage, die auf der Verarbeitung von Spins als Informationseinheiten basieren.

Graphen ist wohl die exotischste Form von Kohlenstoff: Alle Atome sind untereinander nur in der Ebene verbunden und bilden ein Netz mit sechseckigen Maschen,...

Alle Focus-News des Innovations-reports >>>



im innovations-report
in Kooperation mit academics

11. BusinessForum21-Kongress „Aktives Schadenmanagement"

22.09.2017 | Veranstaltungen

Internationale Konferenz zum Biomining ab Sonntag in Freiberg

22.09.2017 | Veranstaltungen

Die Erde und ihre Bestandteile im Fokus

21.09.2017 | Veranstaltungen

Weitere VideoLinks >>>
Aktuelle Beiträge

11. BusinessForum21-Kongress „Aktives Schadenmanagement"

22.09.2017 | Veranstaltungsnachrichten

DFG bewilligt drei neue Forschergruppen und eine neue Klinische Forschergruppe

22.09.2017 | Förderungen Preise

Lebendiges Gewebe aus dem Drucker

22.09.2017 | Biowissenschaften Chemie