In just three weeks this fall, thousands of people playing the free downloadable game helped map the structure of an enzyme that could fight HIV and AIDS. Scientists at the University of Washington created Fold-it to turn research about protein folding into a game, dishing up puzzles made up of spirals and clumps that represent amino acids.

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Khatib decided to share a longstanding problem in AIDS research in the form of Foldit, a program that reframes scientific challenges as a competitive multiplayer computer game.

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