Natures wonders: magnetic field migration (Introduction)

by David Turell @, Tuesday, November 17, 2015, 15:25 (3292 days ago) @ David Turell
edited by David Turell, Tuesday, November 17, 2015, 15:36

A new protein complex which aligns with the magnetic field is found:-http://www.the-scientist.com/?articles.view/articleNo/44478/title/Biological-Compass/-"A variety of different animal species possess remarkable navigational abilities, using the Earth's magnetic field to migrate thousands of miles every year or find their way home with minimal or no visual cues. But the biological mechanisms that underlie this magnetic sense have long been shrouded in mystery. Researchers in China may have found a tantalizing clue to the navigational phenomenon buried deep in the fruit fly genome. The team, led by biophysicist Can Xie of Peking University, discovered a polymer-like protein, dubbed MagR, and determined that it forms a complex with a photosensitive protein called Cry. The MagR/Cry protein complex, the researchers found, has a permanent magnetic moment, which means that it spontaneously aligns in the direction of external magnetic fields. -
“'This is the only known protein complex that has a permanent magnetic moment,” said Peter Hore, a physical chemist at the University of Oxford, U.K., who was not involved in the research. “It's a remarkable discovery.”
 (my bold)-"Determining that MagR and Cry were highly expressed and colocalized in the retinas of pigeons, Xie's team focused on that species to conduct further experiments to ferret out the structure and behavior of the protein complex. Using biochemical co-purification, electron microscopy, and cellular experiments in the presence of a magnetic field, the researchers constructed a rod-shaped model of the MagR/Cry complex, and suggested a potential mechanism for how the complex might work in situ to sense magnetism. “It is quite convincing that this complex may be the magnetoreceptor, at least for the organism they have fished it out from,” Chou said. “I think it's a great step forward to open this whole mystery.”-"Cry likely regulates the magnetic moment of the rod-shaped complex, while the iron-sulfur clusters in the MagR protein are probably what give rise to the permanent magnetic polarity of the structure. “The nanoscale biocompass has the tendency to align itself along geomagnetic field lines, and to obtain navigation cues from a geomagnetic field,” Xie wrote. “We propose that any disturbance of this alignment may be captured by connected cellular machinery such as the cytoskeleton or ion channels, which would channel information to the downstream neural system, forming the animal's magnetic sense (or magnetic ‘vision').”-"Hore was cautious about saying that the newly modeled complex is absolutely responsible for magnetoreception in animals. “I don't think I would say that its game-changing, but it is very interesting and will prompt a lot of experimental and theoretical work,” he said. “It may be very relevant to magnetoreception, it's just too soon to know.'”-From Phys. Org.:-"The researchers acknowledge that their findings do not prove that the protein complex is responsible for magnetic sensing, but suggest it seems possible—if the protein complex lined up inside the eye of a pigeon, for example, it could cause a reaction with other proteins or even cells, that in turn could impact nerve cells. They note that the protein complex exists in many organisms that have demonstrated magnetic sensing, including in the eyes of pigeons—they are calling on the research community to conduct other studies to determine if removing the complex from magnetic sensing insects or animals, causes them to lose their magnetic sensing abilities, which could indirectly prove that they form the basis for the ability. If such efforts prove fruitful, then the next logical step would be to study the complex further as it exists inside living animals to determine exactly how it works." 
 
Comment: My bolded section is an excellent example of specified complexity. How did the process of chance evolution search and find such a molecule to use this way?


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