Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Filming an ultra-fast biological reaction essential to life

25.06.2003


Migration of the CO after photolysis. The sites that are currently occupied by the CO are marked by solid yellow circles. Sites from which the CO has departed are depicted by a dotted yellow circle


A team of scientists from the USA in collaboration with staff at the European Synchrotron Radiation Facility (Schotte et al) have managed to film a protein at work in unprecedented detail. The protein is the oxygen-storing molecule myoglobin, which plays a central role in the production of energy in muscles. The motion of the protein was recorded using ultra-short flashes of X-ray light from the synchrotron. The new insight in the functionality of myoglobin has led to a deeper understanding of the molecular processes associated with respiration. An article on the subject was published Friday 20 June in "Science" under the title Watching a Protein as it Functions with 150-ps Time-Resolved X-ray Crystallography.

Every time we contract a muscle, myoglobin releases oxygen which is used by all mammals for the production of energy. Muscle cells use myoglobin as a peak-load buffer when blood cannot supply oxygen fast enough, for example when the circulation is blocked during muscle contraction. The oxygen molecule is initially confined in a cavity called the heme-pocket, where it is chemically bound to an iron atom.

The three-dimensional pictures taken at the ESRF resolve positions of all the 1432 atoms in the protein, and pinpoint how the carbon monoxide (CO) molecule – used here as a replacement for oxygen (O2) for technical reasons - literally finds its way out of the very dense atomic structure near the iron atom. The scientists have discovered that the CO molecule does not move out smoothly; in fact it spends most of its time captured in 5 tiny cavities inside the protein. In the first cavity near the iron atom, the CO molecule makes an extremely brief visit lasting only 100 picoseconds2, i.e. a tenth of a billionth of a second. Iron would naturally try to rebind CO, but nearby molecules block the CO from going back to the iron. The film has shown that the motion between the 5 cavities is very fast. The CO molecule reaches the fifth cavity after 30 nanoseconds and then it disappears into the solvent surrounding the protein. The interesting thing is that eventually another CO molecule, released from a myoglobin molecule nearby, will diffuse back towards the iron, most likely through another route. The iron accepts the incoming CO due to the fact that the structure of the protein has changed to allow for the rebinding.



Watching myoglobin as it functions is more complicated than it may seem. First of all, the scientists have to control the start of the experiment extremely precisely. The experiment begins by the injection of a flash of laser light to perturb the molecules and release the CO molecule inside the protein. Very shortly afterwards, they expose the protein crystal to an intense flash of X-rays. The X-rays are scattered by the protein into diffraction3 pictures that are later analysed by computers. The duration of an X-ray flash from the synchrotron is as short as 100 picoseconds and that is in principle the shortest time duration that can be investigated at the ESRF.

About the “scenario” for the filming

The live filming of the protein took place in ID09, one of the 40 beamlines at the ESRF. A beamline is a laboratory for X-ray studies. The X-ray radiation enters the experimental cabin and “shoots” on a sample, in this case, a crystallised protein. This beamline, called White Beam Station, is a beamline designed for time-resolved experiments in macromolecular crystallography and liquids, and also for high pressure research. Its unique feature is the focused white beam, which can be used for time-resolved diffraction on macromolecules.

Montserrat Capellas | alfa
Further information:
http://www.esrf.fr/News/FrontNews/PressRelease_23-06-2003/

More articles from Interdisciplinary Research:

nachricht Magnetic nanopropellers deliver genetic material to cells
08.05.2020 | Max-Planck-Institut für Intelligente Systeme

nachricht Development of new system for combatting COVID-19 that can be used for other viruses
08.04.2020 | University of Texas Medical Branch at Galveston

All articles from Interdisciplinary Research >>>

The most recent press releases about innovation >>>

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

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

Im Focus: NASA's Curiosity rover finds clues to chilly ancient Mars buried in rocks

By studying the chemical elements on Mars today -- including carbon and oxygen -- scientists can work backwards to piece together the history of a planet that once had the conditions necessary to support life.

Weaving this story, element by element, from roughly 140 million miles (225 million kilometers) away is a painstaking process. But scientists aren't the type...

Im Focus: Making quantum 'waves' in ultrathin materials

Study co-led by Berkeley Lab reveals how wavelike plasmons could power up a new class of sensing and photochemical technologies at the nanoscale

Wavelike, collective oscillations of electrons known as "plasmons" are very important for determining the optical and electronic properties of metals.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

25.05.2020 | Medical Engineering

New gravitational-wave model can bring neutron stars into even sharper focus

22.05.2020 | Physics and Astronomy

A replaceable, more efficient filter for N95 masks

22.05.2020 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>