Tender X-rays show how one of nature’s strongest bonds breaks
Short flashes of an unusual kind of X-ray light at SwissFEL and SLS bring scientists closer to developing better catalysts to transform the greenhouse gas methane into a less harmful chemical.
How to get chloride ions into the cell
A molecular movie shot at PSI reveals the mechanism of a light-driven chloride pump
EU XFEL Young Scientist Award for Camila Bacellar
Camila Bacellar, beamline scientist and group leader of the Alvra endstation at SwissFEL, has received the European XFEL Young Scientist Award. The award recognises the contribution of young scientists to research at the European XFEL.
Unerwartetes Aufwölben eines Proteins
Forschende haben dem lebenswichtigen Protein Cytochrom C ein Geheimnis entlockt, das dieses bisher gut zu verbergen wusste. Messungen am Freie-Elektronen-Röntgenlaser SwissFEL zeigen Strukturänderungen, welche die Wissenschaft für diese Art von Biomolekül bisher ausgeschlossen hatten.
Advances in de novo protein structure determination using long-wavelength native-SAD phasing at SwissFEL
An international team of scientists from the Paul Scherrer Institute and members of the LeadXpro and Heptares pharmaceutical companies led by Karol Nass (Alvra group, SwissFEL) demonstrated a significant advancement in de novo protein structure determination at X-ray free-electron lasers. Their article, published recently in IUCrJ (DOI: 10.1107/S2052252520011379), describes structure determination of a membrane protein and an important drug target (A2A adenosine receptor) by native single-wavelength anomalous diffraction (native-SAD) at SwissFEL with up to ten fold reduction in the required number of indexed images.
Unraveling the structural dynamics of Heme proteins at SwissFEL
The results from the very first user experiment at SwissFEL have just been published in the Proceedings of the National Academy of Sciences (PNAS). The measurements probed the electron transport properties of the cytochrome c protein, which is found in cellular mitochondria. The measurements show that when the Fe atom at the centre of the protein undergoes electronic excitation, for example when it gains or loses and electron, the active centre of the protein undergoes a doming structural rearrangement. This result raises interesting questions about how this structural change is involved in the electron transfer properties of cytochrome c.
Mechanismus einer lichtgetriebenen Natriumpumpe aufgeklärt
Forschenden des Paul Scherrer Instituts PSI ist es erstmals gelungen, eine lichtgetriebene Natriumpumpe von Bakterienzellen in Aktion aufzunehmen. Die Erkenntnisse versprechen Fortschritte bei der Entwicklung von neuen Methoden in der Neurobiologie. Für ihre Untersuchungen nutzten die Forschenden den neuen Freie-Elektronen-Röntgenlaser SwissFEL.
Auf der Suche nach dem Leuchtmaterial der Zukunft
Am Paul Scherrer Institut PSI haben Forschende Einblicke in ein vielversprechendes Material für organische Leuchtdioden (OLEDs) erhalten. Das neue Verständnis wird helfen, Leuchtmaterialien mit hoher Lichtausbeute zu entwickeln, die kostengünstig herzustellen sind.
First serial femtosecond crystallography experiment using SwissFEL’s large bandwidth X-ray pulses
The typical mode of operation at XFEL facilities uses the so-called self-amplified spontaneous emission (SASE) process to generate the short, bright X-ray pulses. This mode of operation is stochastic in nature, causing some variance in intensity and spectrum on a shot-to-shot basis, which makes certain types of crystallographic measurements much more challenging.
Towards X-ray Transient Grating Spectroscopy at SwissFEL
The high brilliance of new X-ray sources such as X-ray Free Electron Laser opens the way to non-linear spectroscopies. These techniques can probe ultrafast matter dynamics that would otherwise be inaccessible. One of these techniques, Transient Grating, involves the creation of a transient excitation grating by crossing X-ray beams on the sample. Scientists at PSI have realized a demonstration of such crossing by using an innovative approach well suited for the hard X-ray regime.
First femtosecond protein pump-probe measurements at SwissFEL
A major milestone in the commissioning of SwissFEL has been reached: the first pump-probe experiments on proteins have been successfully carried out. Crystals of several retinal-binding proteins were delivered in a viscous jet system and a femtosecond laser was used to start the isomerization reaction. Microsecond to sub-picosecond snapshots were then collected, catching the retinal proteins shortly after isomerization of the chromophore.
Demonstration of femtosecond X-ray pump X-ray probe diffraction on protein crystals
Our experiments, published in the September issue of Structural Dynamics, demonstrate the feasibility of time-resolved pump-multiprobe X-ray diffraction experiments on protein crystals using a split-and-delay setup which was temporarily installed at the LCLS X-ray Free Electron Laser.
First serial femtosecond crystallography (SFX) pilot user experiment at SwissFEL
On the 7th to 12th of August 2018, a collaborative group of scientists from the Paul Scherrer Institute and members of the LeadXpro and Heptares pharmaceutical companies led by Karol Nass (PSI macromolecular crystallography MX-SLS group) performed the first serial femtosecond crystallography (SFX) pilot user experiment at the SwissFEL X-ray free electron laser (XFEL).
Biologischer Lichtsensor in Aktion gefilmt
Mithilfe eines Röntgenlasers hat ein Team unter Leitung von Forschenden des Paul Scherrer Instituts PSI einen der schnellsten Prozesse in der Biologie aufgezeichnet. Der dabei erzeugte molekulare Film enthüllt, wie der Lichtsensor Retinal in einem Proteinmolekül aktiviert wird. Solche Reaktionen kommen in zahlreichen Organismen vor. Der Film zeigt erstmals, wie ein Protein die Reaktion des eingebetteten Lichtsensors effizient steuert.
Identification of hole trapping sites in ZnO nanomaterials
Members of the Alvra group led an investigation into the fate of charge carrier dynamics in metal oxide semiconductor nanomaterials. The experiments were performed at the Advanced Photon Source (Argonne, IL, USA) and used a PSI-designed von Hamos geometry X-ray emission spectrometer that was constructed for the experiment to perform resonant XES measurements on a solution of 32 nm diameter ZnO nanoparticles photo-excited with 3.2 eV (355 nm) short laser pulses. The measurement showed that the hole-trapping takes place within less than 100 ps and the trapping site in the ZnO crystal lattice is at oxygen vacancies in the lattice. The trapping of the hole results in a local structural distortion, where the four neighbouring Zn atoms move away from the vacancy. The measurement demonstrated the strength of the RXES technique's ability to probe both the electronic and geometric structure of materials and the results were recently published in Nature Communications.
First Pilot Experiment at SwissFEL-Alvra: UV photo-induced charge transfer in OLED system
On the 17th of December 2017 SwissFEL saw its first pilot experiment in the Alvra experimental station of the SwissFEL ARAMIS beamline.
A three-dimensional movie of structural changes in bacteriorhodopsin
Snapshots of bacteriorhodopsinBacteriorhodopsin is a membrane protein that harvests the energy content from light to transport protons out of the cell against a transmembrane potential. Nango et al. used timeresolved serial femtosecond crystallography at an x-ray free electron laser to provide 13 structural snapshots of the conformational changes that occur in the nanoseconds to milliseconds after photoactivation. These changes begin at the active site, propagate toward the extracellular side of the protein, and mediate internal protonation exchanges that achieve proton transport.
Gemeinsam statt einsam
An SwissFEL und SLS Biomoleküle entschlüsseln: Proteine sind ein begehrtes, aber widerspenstiges Forschungsobjekt. Eine für Freie-Elektronen-Röntgenlaser wie dem zukünftigen SwissFEL des PSI entwickelte Methode soll ihre Erforschung nun ein grosses Stück vorantreiben. Dabei werden viele identische, kleine Proteinproben in kurzen Abständen hintereinander mit einem Röntgenstrahl durchleuchtet. Damit wird ein bisheriges Hauptproblem der Erforschung von Proteinen umgangen: Proben in ausreichender Grösse herzustellen.
Gespaltener Röntgenblitz zeigt schnelle Vorgänge
SwissFEL, der Röntgenlaser des PSI, wird die einzelnen Schritte sehr schneller Vorgänge sichtbar machen. Ein neues Verfahren soll besonders genaue Experimente ermöglichen: Dabei werden die einzelnen Röntgenblitze in mehrere Teile aufgespalten, die nacheinander am Untersuchungsobjekt ankommen. Das Prinzip des Verfahrens erinnert an die Ideen der frühesten Hochgeschwindigkeitsfotografie.