Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Extreme x-ray pulses create unique image of intact virus

03.02.2011
They are entirely too small to be seen even with the most powerful microscope.

But now an international research team has managed to capture an image of an intact virus and a membrane structure from a photosynthetic bacterium with the aid of extremely intensive and ultra-short x-ray pulses from the world’s first free electron laser. This new advance in structural biology is being published today in two articles in the journal Nature.

The findings for the two studies pave the way for studies of biological structures at the molecular level, including viruses, individual cells, cell organelles, and living bacteria. The technology enhances the possibilities of imaging individual biological molecules that are too small to study even with the most powerful microscopes.

- Biologists have long dreamed of being able to capture the image of viruses, single-cell organisms, and bacteria without having to section, freeze, or mark them with metals, as is necessary in electron microscopy. Our studies show that it is really possible to create images with the aid of extremely intensive and ultra-short x-ray pulses that would otherwise destroy everything in their path, says Professor Janos Hajdu from the Division of Molecular Biophysics, Uppsala University.

Together with his colleague Henry Chapman, he has co-directed the international research team, which also includes Inger Andersson’s team from the Swedish University of Agricultural Sciences, SLU. The entire international group is currently at Stanford for new experiments with the advanced free electron laser.

X-ray diffraction has been an irreplaceable instrument in identifying biological structures, but this technology requires crystallized samples of sufficient size. Many particles are therefore packed in crystals. For single particles the x-ray dose needs to be increased so much that the particle is destroyed, especially if it comes from biological material. A number of years ago it was suggested that extremely short pulses from a so-called free electron laser would be able to create an image before the particle had time to be damaged. It is this method (read more about the technology below) that is now being tested on biological material.

In the first study, the method was tested on Mimivirus, the world’s largest known virus, discovered as recently as 1992. It is larger than some single-cell organisms and the only virus that can be infected by a virus of its own. Its size and special surface structure entails that it cannot be studied using conventional imaging methods such as electron microscopy or x-ray crystallography.

In the other study the team shows that x-ray pulses can also be used to study the structure of vitally important membrane proteins – in this case a protein complex that captures sunlight and converts it to energy in photosynthesizing organisms, here a photosynthetic bacterium. Membrane proteins are essential to life processes, not only as energy converters but also as the cell’s transporters and receptors for drugs – but they are incredibly hard to study using conventional methods. The new technology means that huge “blank patches” in structural biology will now be accessible for study at the level of the atom for the first time.

About the technology: The world’s first free electron laser in the hard x-ray area – the Linac Coherent Light Source (LCLS), at Stanford Linear Accelerator Center (SLAC) – has a light intensity that surpasses conventional synchrotrons by a billion times, so intensive that it can cut through steel. A single pulse that is focused on a micrometer-size point contains as much energy as all sunlight hitting the earth focused to a square millimeter. The light pulses are extremely short (50-70 femtoseconds, 1 fs = 10-15 sec), which means that can replicate the image of a micrometer-size virus, before it is heated up to 100,000 degree centigrade and is destroyed. LCLS came into use in October 2009, and the studies in question were performed in December that year.

References:

Hajdu et al. Single mimivirus particles intercepted and imaged with an X-ray laser. Nature, doi:10.1038/nature09748

Chapman et al. Femtosecond X-ray protein nanocrystallography. Nature, doi:10.1038/nature09750

For more information, please contact Janos Hajdu (currently at Stanford), mobile: +46 (0)70-425 01 94, janos.hajdu@icm.uu.se or Inger Andersson (also currently at Stanford), mobile: +46 (0)70-520 81 01, inger.andersson@molbio.slu.se

Uppsala University -- quality, knowledge, and creativity since 1477
World-class research and outstanding education of global benefit to society, business, and culture.

Uppsala University is one of northern Europe's highest ranked academic institutions.

Anneli Waara | Uppsala universitet
Further information:
http://www.uu.se

More articles from Physics and Astronomy:

nachricht Basque researchers turn light upside down
23.02.2018 | Elhuyar Fundazioa

nachricht Attoseconds break into atomic interior
23.02.2018 | Max-Planck-Institut für Quantenoptik

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>