Researchers discover water's role in brain learning and memory signaling
· News-MedicalIf you think back to chemistry class, you might remember that calcium and magnesium sit close together on the periodic table. They also carry the same electrical charge. That makes it hard to tell them apart. One key difference is that "magnesium attracts water more strongly than calcium," Furukawa says. "It's more difficult to take out water molecules surrounding magnesium than calcium."
Since the 1980s, scientists have thought this might explain why calcium passes through the NMDAR channel more easily. It made sense. However, it was impossible to observe. It took decades for imaging technology and computing power to catch up with the theory. But now, using a method called single-particle cryo-EM, Steigerwald and his colleagues have demonstrated how dehydration enables calcium to pass through the NMDAR channel.
Steigerwald focused his attention on a part of the channel known as the Asn cage. This molecular cage acts as a filter, allowing only molecules that are small enough to pass. Outside the filter, the team saw magnesium surrounded by water, blocking the channel. If you're picturing a backed-up spaghetti strainer, you're right. "It's a sieve," Furukawa explains.
So that covers water, dehydration, and the molecular cage. But how do 50,000 movies fit into the picture? "It's all about resolution," Furukawa says.
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