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.
Montserrat Capellas | alfa
Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs
07.11.2017 | Technische Universität München
NRL clarifies valley polarization for electronic and optoelectronic technologies
20.10.2017 | Naval Research Laboratory
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
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Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
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15.11.2017 | Event News
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22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy