MacKinnon shared the prize with Peter Agre of the Johns Hopkins University. Agre is currently a member of HHMI's scientific review board. The two scientists were honored for discoveries clarifying "how salts (ions) and water are transported out of and into the cells of the body," according to the Royal Swedish Academy of Sciences.

"This is appropriate recognition for the beauty of MacKinnon's science and the clarity with which he expresses the biological phenomenon," said HHMI President Thomas R. Cech, who won the Nobel Prize in Chemistry in 1989. "MacKinnon's work is exquisite, but he also makes the data come alive with very thoughtful and clear explanations."

In 1998, much to the surprise of colleagues, MacKinnon and his colleagues determined the three-dimensional structure of a pore that allows cells to control their intake of potassium ions. By determining the structure of the potassium pore, or channel, MacKinnon and his colleagues at The Rockefeller University had solved a riddle that has perplexed biophysicists for decades: How does a potassium channel admit millions of potassium ions per second, while allowing only one smaller sodium ion to slip through for every 1,000 potassium ions?

The answer is important because potassium channels are part of the apparatus that maintains the normal ionic balance across the cell membrane. In excitable cells, like those in nerves and muscles, for example, the channels help re-establish the electrical difference between the inside and outside of the cells after excitation. Without potassium and sodium channels, neurons could not generate electrical signals and hearts could not beat rhythmical
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Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
8-Oct-2003