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.
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, email@example.com or Inger Andersson (also currently at Stanford), mobile: +46 (0)70-520 81 01, firstname.lastname@example.orgUppsala University -- quality, knowledge, and creativity since 1477
Uppsala University is one of northern Europe's highest ranked academic institutions.
Anneli Waara | Uppsala universitet
Smallest transistor worldwide switches current with a single atom in solid electrolyte
17.08.2018 | Karlsruher Institut für Technologie (KIT)
Protecting the power grid: Advanced plasma switch for more efficient transmission
17.08.2018 | DOE/Princeton Plasma Physics Laboratory
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences