For years, biologists have pondered how so many members of the animal kingdom -- from fruit flies and pigeons to sea turtles and wolves -- are able to navigate long distances apparently by sensing the Earth's magnetic field. Two theories have emerged in recent years: one that the ability derived from iron-binding molecules, the other that it came from a protein called cryptochrome. Now a team from China's Peking University have discovered that both theories describe complimentary aspects of the same bio-navigational system.
To test their hypothesis, the research team first search for a protein with four very specific properties: that it be able to bind iron, do so within the cell (rather than on the cell membrane), operate within the central nervous system and interact with cryptochrome. They found it in a protein called MagR. Turns out that the molecular shapes of MagR and cryptochrome compliment each other to form a cylindrical shape which is highly magnetic. When exposed to a magnetic field, these proteins literally flew off the lab bench and adhered themselves to the team's metal instruments.
The team believes that these proteins act like a compass needle. When the animal turns, these molecules likely remain locked pointing North, thereby informing the animal of its relative heading change. Next, the team will now look into extracting (or at least suppressing the expression of) these proteins to see if animals lose their natural navigation abilities. Their current research was recently published in the journal Nature Materials.
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